# ensuring highest oxygen levels... expert opinions?



## gherlevi (Dec 16, 2004)

I wanted to ask a slightly theoretical question, but I think it's worth considering. How do you ensure that the tank water is saturated with as much oxygen as possible?

The general answer is "surface agitation," but I'm thinking specifically about whether or not a wet/dry filter offers yet more oxygen than agitating the heck out of a tank surface.

Here's an example: I have a 65 gallon tank, with a 3 foot length. Filtration is an Eheim 2217 and an AC 70. The entire upper surface is totally agitated, with no dead spots.

If I were to substitute a wet/dry setup, do I gain any advantage of extra oxygenation? I'm trying to think of a reason why I'd want or need wet/dry filtration, other than the added buffer and dilution of extra gallons of water, and the ability to hide equipment.

Please share your thoughts! I'm curious to hear what people think, especially those that have run both canisters and wet/dry.


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## lloyd (Aug 24, 2005)

this 'article'...: http://www.lamotte.com/pages/common/techtips/dotip.html offers a bit of excess detailing, but also hints at a few important considerations relevant to aquaria. for example: removing excess detritus, allowing some algae to remain in the tank, fresh water input, low bio loads, etc...
personally, i do not think any store bought filtration devices have the capacity to influence d.o. content to any significant measure. i have seen a DIY sand bed filter, with an oxygen infuser added, that did leave me impressed with the attempt though. you might try to infuse air into the return of your canister, but only a test kit would offer you concrete answers to your efforts, and excessive oxygenation can be as stressful to fish as the lack of same. IMHO.


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## gherlevi (Dec 16, 2004)

Interesting article. The idea of including algae and plants in the equation is an important point!

From what I gather based on your comments, it's basically a "wash" regarding using canister or other means to churn/agitate the surface vs. using a wet/dry setup?


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## smellsfishy1 (May 29, 2008)

I have always wondered similar thoughts in respect to how much oxygen is in the water and how much oxygen it can actually hold or even what is the optimal level of oxygen.
Most of the time we are told or given advice to do the best we can with filteration and surface agitation but what about a true value.
It obviously is not something we can quantify easily. I don't know of any test kit or machine that can actually measure the amount of oxygen in water. Maybe someone knows of one or the other.
If there was such a measure, is there a point where it reaches saturation and adding oxygen through surface agitation, infusion, wet/dry, or algae/plants is no longer necessary?
I just thought I would throw it out there, I didn't mean to take the thread away, just curious on the nature of oxygen levels since we all strive to achieve the best conditions for our fish.


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## Toby_H (Apr 15, 2005)

A wet dry and an HOB use the same method to add oxygen to the water... aggitation... So I don't see how one should be assumed to do any better than the other.

Although proper water movement can have a major impact on oxygenation. No matter how much oxygen you get into the water at the surface, it won't help stale dead spots at the bottom. Such dead spots are possible with any kind of filtration (Sump, Canister, HOB, etc).

In many years of fish keeping I've never struggled to properly oxygenate the water. What is your motivation to exolore this theory with such attention to detail?


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## iceblue (Apr 27, 2004)

It would seem to me the greater exchange is made at the water surface. Having a large sump that is longer and wider then it is deep will greatly enhance this ability and give this type of system imho an advantage over cannisters.

If anybody out there has any mad cash we could put it to test and rest.
http://www.uvprocess.com/product.asp?code=OXYTEST++C opcorn:


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## smellsfishy1 (May 29, 2008)

WOW! That meter is 500 bones. For a half a stack I could buy my dream tank with all the plants, pumps, filters, and oxygen infusors I could need. :lol:


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## gherlevi (Dec 16, 2004)

Hey Smellsfishy1, you're not hijacking the thread at all... your questions are on par with my questions...

There's a practical reason behind my initial questioning. Take that 65 gallon tank, with an AC 70 HOB and Eheim 2217 canister. I plan on keeping a colony of tropheus, and I know they need "well-oxygenated water" in a relatively tall tank. Does my filtration cover it? If not, does it make a difference whether I add a wet-dry or another large canister?

It sounds like, no matter what filtration you are using, if you are sufficiently agitating the surface and moving water through all portions of your tank, you're in good shape. There's nothing inherent about a wet-dry that makes it more capable of saturating tank water with dissolved oxygen than a canister or HOB.

that's what I'm kind of prying at. Why spend approx. $200 on getting a wet-dry setup if it offers no real advantages in increased oxygenation (this assumes the current setup is handling the nitrogen cycle, that water changes are being done appropriately, etc. etc.)


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## smellsfishy1 (May 29, 2008)

I think the wet/dry can offer some advantages in certain applications. It probably would be to your advantage to use one in a tall setup but you don't have to spend $200 to do so.
You could get some idas on the DIY threads. Being a 60 gallon, a good quality canister should be all you need. An added bonus would be the HOB.
I agree with you gherlevi, if the water changes are on point and you have water movement/agitation/filtration maximized it is all covered.


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## Toby_H (Apr 15, 2005)

Well on one hand I agree that a wet/dry offers no added benefits in regards to oxygenation...

But on the other hand I think the added volume that a sump (wet/dry) offers can only make things better for your fish. Even if your current filtration keeps ammonia/nitrite at zero... you still have nitrates. If your sump adds 50% to your current volume then it will also dilute/reduce your nitrates by 33%... roughly...


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## gherlevi (Dec 16, 2004)

Hey Toby-H, thanks for chiming in.

I agree that a wet/dry and sump offers other advantages, which started my thinking on this in the first place. #1 was my questioning about improved oxygen exchange, and #2 was the benefits of increased water volume. I'm probably going to end up "overstocking" this tank, and I might want those extra water volume long term.

Or...

I can just be really agressive with water changes. I guess it ultimately depends on my laziness!

For now, I probably have a least a year with my current filtration setup. It gives me time to save up in case I do decide to go wet-dry.

My one gripe with most pre-made sumps is that they seem so dang small! If increased water volume is one of the primary advantages, why do most commercial sumps hold approx. 10 or 15 gallons?! Seems a shame.

Only thing that caught my eye is the Eshopps wet-dry that's on Drs. fostersmith. It begins to approach a cost that competes with taking the time to do a DIY setup.


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## iceblue (Apr 27, 2004)

I agree with Smells, a 60 gallon with good surface turbulence and good bottom circulation should be more then adequate in a 60 gallon using a good canister. Most wet/dry's on the market are compact by nature and don't offer much in the way of larger water capacity (surface area). Tidepool wet/dry filters may be an exception.

When you get up to the 125g and larger is where wet/dry's really come into prominence. For the do it yourselfers a cheap wet/dry is easy enough to set-up. Any container that will hold water will do as a sump. The only limiting factor is having the room to place it. The wet/dry portion is also fairly simple. It only has to hold your bio-media and some mechanical filtration and be able to transfer water to the sump. A 5 gallon bucket and plastic storage bin would make a fine wet/dry filter and would be far less in cost then buying them commercially. The biggest outlay in money would be for the pump to run it.

When it comes to air exchange though I still think the more surface area you can get the better it would be for your livestock. It may just be ad-hoc but it makes sense to me.


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## dwarfpike (Jan 22, 2008)

I'm not sure about disgarding the wet/dry for adding to the disolved oxygen. It's long been said to help in that regard, especially with fish from fast flowing waters and high oxygen content. Zebra plecos were a good example, when first imported no one seemed to be able to keep them alive until wet/drys were used.

Now becuase of all the other benefits, it is hard to tell if it was indeed the dissolved oxygen that helped or the extra biological filtration, or more water volume, ect. I just think there are way too many stories about fish from rapids not doing well until wet/drys are used (_Telocichla, Telogramma_, ect) to make it seem like coincidence for me.


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## prov356 (Sep 20, 2006)

I think you can oxygenate water just fine with a lot of different filters and setups. Most fish appreciate 
well oxygenated water. I think when you hear that about a particular fish, they're really saying don't try to 
keep this fish in a tank that sometimes gets neglected to the point of filters slowing down. When that 
happens, circulation and agitation suffer and oxygen content may drop. But then you also are 
dealing with elevated levels of DOC's, etc. So, I'd just interpret that to mean don't try to keep these fish 
in a neglected tank without being concerned with 'what's my oxygen content?'.

Regarding the wet/dry's inherent ability to oxygenate water, seems no one's mentioning the surface 
area of the trickling water. It's not the surface area of the sump water that gives a wet/dry it's 
reputation for oxygenation. Wet/dry's have media above the water line of a sump that water is trickled 
through. That's the whole idea. As a thin layer of water trickles through the biomedia, it has every 
opportunity to take on oxygen. An opportunity that doesn't exist in a canister filter. So, IMHO, there is 
no comparison between the ability of a wet/dry to oxygenate vs. the ability of a closed canister to do 
the same, all things being equal. You can use a spray bar at the surface, I know, but you can do the 
same with the returns of a wet/dry. This oxygenated water, btw, is intended primarily for the nitrifying bacteria, 
not the fish. The idea is that the water is oxygenated as it trickles over the biomedia where the 
nitrifying bacteria reside. This is what gives them their reputation for doing excellent biofiltration. Can 
you do excellent bio in a canister? Of course, so don't flame me please. 

If you want to oxygenate water for the fish, I'd take a different approach. Think surf zone of a lake. Get 
2-3 powerheads with lift tubes that draw water up from the bottom of the tank and then release it hard 
over the surface of the water. You want to simulate waves crashing over shoreline. Now is this 
really necessary for most fish, even the ones that 'require well oxygenated water'? I don't think so, but 
there may be some. Fish that come from shallow streams or shorelines seem to get this label. Are 
they there because they require well oxygenated water or is there some other reason they've 
populated this habitat?

Last point, I really doubt that there have been many, if any, studies done on particular species of fish 
to determine exactly what level of oxygen they require to thrive, so measuring and knowing the level 
in our tanks isn't of much benefit. Not sure what we'd do with that info alone.

Just my .02 again.


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## gherlevi (Dec 16, 2004)

Thanks everyone for the responses! This has been an interesting discussion.

The points I take away from this (for my specific concerns!) are:

--oxygen levels are not really a separate concern, as it's almost always addressed via the more pressing and common concerns such as proper filtration and tank maintenance.

--a wet/dry and sump does not necessarily offer improved oxygen exchange over other sufficient filtration methods, but it's other benefits should not be ignored.

Basically, on my 65 gallon, if I ever decide to add a wet-dry setup, it will be for the benefits of the extra gallons of water to dilute impurities. And, if that's the primary reason, I'll probably go DIY instead of pre-made, because most premade sumps hold a surprisingly small volume of water.


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## lloyd (Aug 24, 2005)

here's a few pictures, of the attempt i've made, to assure my zebra plecos get the water quality they need:
















the first picture, shows how allowing air to vent into my overflow, creates surf agitation where water returns to the 'pre sump' tank. i use this tank to introduce new water during water changes. the second picture illustrates the surface roll, within the tank itself, i achieve by using multiple returns aimed into each other. 
it's my opinion, that trickle/bio ball areas of filtration, are designed for surface bacterias to achieve their own oxygen intakes. if that sounds logical, then the water would actually be reduced of oxygen as it runs through it. also, bacterial demand on oxygen supply, is directly proportionate to population, so depletion of oxygen (at point of filtration) is a very relevant concern regardless of the filtration device used. 
if water falls too aggressively through filtration, in the attempt to affect oxygenation there, then the process of nitrification will be less than ideal. therefore, any oxygenation attempts, either real or futile ( i say futile, because i have no idea if my adaptions are truly effective), should be attempted at other areas of the system. this makes most 'store bought' filtration devices largely ineffective, with regard to re oxygenation issues, IMHO.


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## prov356 (Sep 20, 2006)

Agreed. Oxygenating for fish, and oxygenating for bacteria are best addressed separately. :thumb:


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## iceblue (Apr 27, 2004)

Not to turn this into a canister vs wet/dry but Prov and Lloyd make very good points for targeted dissolved oxygen which the wet/dry does very well. Another benefit is that most wet/dry's do an excellent job of skimming surface scum allowing greater O2 exchange at the aquariums surface.

With the canister you have an almost closed system where the only oxygen exchange takes place at the tanks surface. If using a canister only for filtration it becomes important to have higher gph turnover rates vs tank size and a turbulent surface to prevent scum build up which slows down gas exchange. Another option is an after market surface extractor.
http://www.cichlid-forum.com/reviews/vi ... php?id=957

Personally, on my 84g I use a canister mainly for bio-filtration and a hang on back for mechanical filtration and surface agitation. The two of them together work very well for my crowded Mbuna tank. In another year or two I'll be tearing it down for a new set-up and will definitely be switching over to a wet/dry.


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## Toby_H (Apr 15, 2005)

But I thought the conclusion was that although higher oxygen levels may be great for bacteria, they are not any benefit to fish... a typical ammount of surface agitation will provide plenty oxygen for fish...

Also, in your explaination, a canister filter does not allow a gaseous exchange... and we are all well aware that the bacteria needs oxygen... so based on your line of thinking, isn't a canister the worst place to cultivate bacteria?

Although I will admit at this point I'm splitting hairs. There is plenty of oxygen in a canister to support bacteria... which needs more oxygen than fish... which further proves the point, there is plenty of oxygen in a tank with simple surface agitation to support fish as well as bacteria...


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## corrie22 (Oct 11, 2008)

I would think that most aquarium filters would have to pull oxygen out of the water.
Canisters, under gravel filters, even hang on the back, all rely on the oxygen in the water for the aerobic bacteria.
Wet/drys were designed so that the dry part was exposed to air, originally called dry/wet, hopefully exposing the bacteria to oxygen in the air, and helping to off gass any CO2, etc.


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## iceblue (Apr 27, 2004)

Toby_H said:


> Also, in your explaination, a canister filter does not allow a gaseous exchange... and we are all well aware that the bacteria needs oxygen... so based on your line of thinking, isn't a canister the worst place to cultivate bacteria?


My canister works just fine at bio-filtering and except for a sponge for mechanical it's packed with bio-media. All my air exchange is done at the surface of my tank. I believe that's why it's recommended to have higher turnover rates for a canister in relation to tank size. Even a blind dog will catch a biscuit if you throw enough off them past his face.


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## boredatwork (Sep 14, 2007)

I think there are a lot of weird assumptions being made here.

One assumption is that the hypothetical oxygenation capability of a any of the filtration methods has any advantage over a different filtration method. I am not saying it doesn't, but I don't think we can say that it does.

In other words, if a wet/dry can provide twice as much oxygen to a tank as a HOB, we are saying that makes it better. But if there is only a demand for 10% of the original oxygen concentration then who cares which filtration method provides more oxygen? I think the assumption has been that more oxygen is better. I am not saying more oxygen is not better, but I don't think we can say that it is necessarily beneficial.

Another assumption is that a particular filtration method can increase water oxygenation. In other words if we pretend that a tank with no filter exchanges oxygen (at the surface, through biological processes inside the tank, etc) at a certain rate, we are assuming that a particular type of filtration added to the tank will increase that exchange rate. But it could be possible that the inherent exchange rate of the tank itself without the filter has already exceeded the maximum oxygen exchange rate, so any filtration may not have any effect on oxygen concentration. Again, I am not saying that a filter will not provide more oxygen, but I don't think we can really say that it does.

I don't think any of the points made so far are invalid in and of themselves, but without an ability to test some of these assumptions I think the discussion becomes somewhat pointless.


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## boredatwork (Sep 14, 2007)

I forgot to add one clue. There have been tests done that show that some filters are better than others at cycling a tank. How much that is related to oxygenation I don't know, but it could be related.


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## corrie22 (Oct 11, 2008)

I think you should all be more concerned about getting rid of CO2.


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## lloyd (Aug 24, 2005)

corrie22 said:


> I think you should all be more concerned about getting rid of CO2.


 your suggestion cannot apply to those attempting to keep, or to those considering to successfully keep, species identified as high d.o. demanding. understanding the role of oxygen within water, and how it builds and/or depletes within an enclosed ecosystem, should be concerning. especially, if keeping species in demand for high content, and again, because of the difficulty in measuring it. 
consider how most fish react to the introduction of new water during regular maintenance. one keeper might assume they simply get excited to nothing in particular, while the more discerning keeper might hypothesize deeper into it, and discover one of the 'secrets' to successful breeding, larger growth, more intense coloration, better recovery rates of illness/infections, etc..
getting rid of co2 is an important issue... but it's only half of the breathing exercise.


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## corrie22 (Oct 11, 2008)

you mean like marine reef fish, that have a extremely high demand on O2?

CO2 is much more soluble, will build up in a tank faster, and in the winter in closed houses can become a huge problem.
People that run marine reef tanks know this and have to even go so far as to vent their tanks to the outside.

That applies to anyone including people keeping marine fish or fresh water fish that like higher O2.
And CO2 is easier to measure, watch your pH.


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## BenHugs (Jan 13, 2007)

Well I'm far from being any kind of expert.
I've always looked at the canisters by... the more fish you have the more bacteria you need which means a much greater amount of 02 as they both will compete for it. I also find it can be loud having the surface agitation in the main tank.
With Wet/drys fish and bacteria no longer compete for 02 and the 02 saturation will be higher based on water volume. All the surface agitation can also take place in the sump.

I do have one bad account with canisters on a heavily stocked tank. I overfilled my tank reducing the surface agitation enough that within 8 hours I had killed half of my stock and I had three fluval 405s on a 130g. That was a bad day


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## prov356 (Sep 20, 2006)

> but without an ability to test some of these assumptions I think the discussion becomes
> somewhat pointless.





> I do have one bad account with canisters on a heavily stocked tank. I overfilled my tank
> reducing the surface agitation enough that within 8 hours I had killed half of my stock and I had three
> fluval 405s on a 130g. That was a bad day Sad


That's why this discussion is important and not pointless. There have been others that have had 
problems like this as well. Having an understanding of how to ensure adequate oxygen levels for both 
fish and filters, whether we can scientifically measure anything or not, is an important basic that 
sometimes doesn't get addressed and bad things happen.



> That applies to anyone including people keeping marine fish or fresh water fish that like
> higher O2.And CO2 is easier to measure, watch your pH.


Are CO2 levels directly adverse to oxygen levels? If not, then it won't help in determining oxygen levels. 
Doesn't mean CO2 isn't important, just not in determining oxygen levels, which is the topic.



> One assumption is that the hypothetical oxygenation capability of a any of the filtration
> methods has any advantage over a different filtration method. I am not saying it doesn't, but I don't
> think we can say that it does.


We can say it hypothetically. If we can't discuss anything until we can set up a lab and prove it 
scientifically, what do we discuss here?


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## gherlevi (Dec 16, 2004)

I haven't posted in a while since I originally posted, but I've kept reading this discussion.

I agree... it's not an either/or option between scientific verification or complete inability to hypothesize. In between, we have anecdotal empirical observation!! The example of the tank with canisters filled too high and consequently losing fish is a valid and concrete example (and also unfortunate!). Sure, we're merely hypothesizing without scientific proof, but if the result is useful "rules of thumb" for filtration, that's still helpful.

Here's my one thought: Is there a more positive "flip side" to this example? Has anyone subbed a wet/dry setup for a previous (and roughly equivalent) canister setup that had average surface agitation and seen noticeable improvements? Sudden breeding? Appearance of better health? That's tough to know what that "equivalent" is. And, we're not "scientifically controlling" to ensure O2 is the only changed variable... but what the hey! Experience still counts, with the proper caveats.


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## lloyd (Aug 24, 2005)

if filter manufacturers could find a way, to prove oxygenation benefits of their product's design over any others, we could bet they would. but they don't....so the safe assumption, IMO, would be that no filter (to date) has any significant affect to boost d.o. in fact, even venturi tools only boast themselves vaguely as 'aeration' devices. 
but we cannot deny, that much success has been achieved, keeping/breeding certain species (in particular for me, the many pleco variants now available as T.R.) previously considered impossible. the details these breeders are focusing on, often includes details to fresh water parameters many of us are still innocently ignorant of. i expect the 'labs' to follow us, as usual, and market something for the masses soon. :wink:


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## prov356 (Sep 20, 2006)

gherlevi said:


> I haven't posted in a while since I originally posted, but I've kept reading this discussion.
> 
> I agree... it's not an either/or option between scientific verification or complete inability to hypothesize. In between, we have anecdotal empirical observation!! The example of the tank with canisters filled too high and consequently losing fish is a valid and concrete example (and also unfortunate!). Sure, we're merely hypothesizing without scientific proof, but if the result is useful "rules of thumb" for filtration, that's still helpful.
> 
> Here's my one thought: Is there a more positive "flip side" to this example? Has anyone subbed a wet/dry setup for a previous (and roughly equivalent) canister setup that had average surface agitation and seen noticeable improvements? Sudden breeding? Appearance of better health? That's tough to know what that "equivalent" is. And, we're not "scientifically controlling" to ensure O2 is the only changed variable... but what the hey! Experience still counts, with the proper caveats.


I think you're running the risk of turning this into a 'which filter is better' thread. I wouldn't 



> the details these breeders are focusing on, often includes details to fresh water parameters many of us are still innocently ignorant of.


lloyd, I'm always interested in this kind of thing. What water parameters are they focusing on 
specifically? Are you saying we'll have manufacturers offering additives and test kits for these 
additives?


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## lloyd (Aug 24, 2005)

prov356 said:


> What water parameters are they focusing on
> specifically? Are you saying we'll have manufacturers offering additives and test kits for these
> additives?


 consider how many tools freshwater keepers must buy/borrow from the salt water section of their LFS to BBD their systems. that's where we got our first sumps, wet/drys, u.v., test kits for anything more than basics, fresh foods, lighting, etc...heck, it seems like only yesterday that power heads finally made it to 'our side' of the store.
some of the better suggestions for breeding difficult types: maintaining d.o. without the stress of constant new water, raising temperatures to simulate seasonal changes, increasing turbidity followed by a calm period, intentional drop of ph, adjusting light exposures to simulate longer/shorter days, periods of fasting followed by a power feed, and fixing m/f ratios to suit.
i doubt we will find too many advanced tools capable of helping freshwater hobbyists at the LFS. we have always been treated like simple comet keepers, IMHO. a 'quiet' or 'hidden' filter seems to be more the rage in technologies for us... :x


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## gherlevi (Dec 16, 2004)

> I think you're running the risk of turning this into a 'which filter is better' thread. I wouldn't


Duly noted, prov356! Certainly not my intention. We already have 30+ posts on this thread.

Maybe there's another control/variable besides switching canister to wet/dry


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## iceblue (Apr 27, 2004)

lloyd wrote:



> consider how many tools freshwater keepers must buy/borrow from the salt water section


 :lol: The only articles I could find on the subject water oxygenation in the home aquaria where somebody actually did some experimenting was on Reefkeepers Online Magazine. It's an interesting read and some of it could/maybe be applied to this discussion. 
Experimental tanks #1 and #2 in the second article seem to be the most germane to our freshwater discussion although Mr. Borneman's conclusions at the end of his second installment are interesting.

1. http://reefkeeping.com/issues/2005-06/eb/index.php
2. http://reefkeeping.com/issues/2005-07/eb/index.php
3. http://reefkeeping.com/issues/2005-08/eb/index.php

Great thread gherlevi. For me it's been thought provoking.


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## prov356 (Sep 20, 2006)

> Great thread gherlevi. For me it's been thought provoking.


For me also. And thanks, iceblue, for the links. Interesting stuff.


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## boredatwork (Sep 14, 2007)

prov356 said:


> > We can say it hypothetically. If we can't discuss anything until we can set up a lab and prove it
> > scientifically, what do we discuss here?


I think that is the question. I know it makes the conversation less interesting, but without any supporting evidence the discussion cannot leave the theoretical and therefore can be pointless in terms of coming to any conclusion of what we can learn and potentially improveme. To have any use it needs to leave the theoretical. In order to make it meaningful you have to know that the ideas being mentioned make sense.

I agree that there are anecdotal stories, but I would equate this discussion to the salt discussion or pH shock discussion. There are many anecdotal stories about using salt (marine and epsom) and how it improves coloration and promotes breeding. But I know for a fact there are people who do not buy this argument because there is no real evidence to support the ideas :wink: .

On the one hand I don't want to say that this discussion is pointless from a hypothetical point of view, but if the ideas cannot be substantiated then I am not sure what can come out of it from a practical point of view.

Now, the articles posted are useful from a somewhat practical perspective. Here is my summary of what I thought were the most relevant conclusions :

1. Powerheads and recirculating pumps do not appear to greatly increase the oxygen saturation state of seawater aquaria. Instead, they probably serve to move oxygenated waters to areas of the tank that are locally lower in oxygen resulting from respiration within the tank.

2. Aquaria can and do become saturated or supersaturated with oxygen during the day, and this is a result of oxygen resulting from irradiance of photosynthetic organisms. *In no case was saturation or supersaturation measured without photosynthesis.* (emphasis mine)

3. Aquaria can and do become hypoxic at night and such a state may pose a risk to hypoxia-intolerant organisms.

4. Airstones and skimmers appear to be a very effective means of oxygenating small water volumes.

I think this is enough to allow the discussion to progress...


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## BenHugs (Jan 13, 2007)

iceblue said:


> lloyd wrote:
> 
> 
> 
> ...


These were great articles. I think the next step would be to get this guy to do a wet/dry vs cannister comparison and put this to rest :thumb:


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## lloyd (Aug 24, 2005)

gherlevi said:


> How do you ensure that the tank water is saturated with as much oxygen as possible? The general answer is "surface agitation," but I'm thinking specifically about whether or not a wet/dry filter offers yet more oxygen than agitating the heck out of a tank surface.


 so it looks like we're stuck with water changes and/or the addition of quick growing greens, with agitation devices being moderately helpful, but no particular filtration device being outstanding.
there are some excellent shipping/packaging concerns, within the articles shared by 'iceblue', so big thanks for that link, also.


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## gherlevi (Dec 16, 2004)

> so it looks like we're stuck with water changes and/or the addition of quick growing greens, with agitation devices being moderately helpful, but no particular filtration device being outstanding.


Lloyd, I'm with you. Your summary is pretty much how I'd summarize this. And that's not necessarily bad. This has been a fascinating thread to read. And, if it's not scientific, I can live with our assumptions. :wink:


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## boredatwork (Sep 14, 2007)

gherlevi said:


> > so it looks like we're stuck with water changes and/or the addition of quick growing greens, with agitation devices being moderately helpful, but no particular filtration device being outstanding.
> 
> 
> Lloyd, I'm with you. Your summary is pretty much how I'd summarize this. And that's not necessarily bad. This has been a fascinating thread to read. And, if it's not scientific, I can live with our assumptions. :wink:


I think the assumptions no longer matter since it seems most people are going along with the articles posted by iceblue. At least now next time we see a question posted about oxygenation we have an answer. Thats the most important part. I know I bookmarked those articles, heh.


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## lloyd (Aug 24, 2005)

boredatwork said:


> I think the assumptions no longer matter...


 assumption is the first breath of hypothesis.


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## iceblue (Apr 27, 2004)

Not to belabor the thread but I think we need to be careful when comparing our freshwater systems to their saltwater counter parts. Salties in general and reef-keepers specifically can be very anal (not meant to be detrimental) about their ecosystems. They have developed a lot of clever ways of maintaining a healthy tank with far less water changes then what would work for our freshwater aquariums. By their nature reef tanks are dependent on photosynthesis for the health of the corals and many of the fish found within these systems are hypoxia resistant.

Most of us maintain a fish only tank and many of us have species that need to be crowded in order to keep some semblance of community. We make very high demands on our water quality and it is incumbent upon us to do regular water changes and to provide as much gaseous exchange as we can. Now I'm not saying that one filter system is better then another. In fact, most of us have healthy tanks no matter what filters we use. The original question as asked by the OP was "How do you ensure that the tank water is saturated with as much oxygen as possible?"

There are two ways by which oxygen enters our tanks. Either by photosynthesis or the gaseous exchange between the water surface and air. In a planted tank with a very light fish-load the photosynthesis may work just fine with minimal filtration. But after the lights are out photosynthesis is worthless for adding oxygen and saturation would declines quickly if you have a heavier fish-load. On the other hand, anything you do to increase the surface area between water and atmosphere will create a higher rate of gaseous exchange and helps to insure the maintenance of oxygen saturation.

I know all these points have already been made but if you go to Article 2 Chart 5 of Bornemans series you see that the course bubbler creates enough water turbulence to get up to maximum oxygenation levels within a given animal population. The foam fractioner also gets to the maximum saturation level but because of it's nature of pulling in huge amounts of tiny bubbles within a smaller volume of water it is able, for lack of a better word, to "spool up" at a much faster rate. I think that one could make the logical hypothetical argument that as fish loads are increased and greater demands are made on oxygen the bubbler would not be able to keep up with the demands as well as the skimmer.

So to answer Gherveli's question: 
"How do you ensure that the tank water is saturated with as much oxygen as possible?"

Drop $380 on a foam fractioner.


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## moi_eater (Jul 11, 2004)

iceblue said:


> So to answer Gherveli's question:
> "How do you ensure that the tank water is saturated with as much oxygen as possible?"
> 
> Drop $380 on a foam fractioner.


Ouch!


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## chc (Jul 28, 2004)

prov356 said:


> I think you can oxygenate water just fine with a lot of different filters and setups. Most fish appreciate
> well oxygenated water. I think when you hear that about a particular fish, they're really saying don't try to
> keep this fish in a tank that sometimes gets neglected to the point of filters slowing down. When that
> happens, circulation and agitation suffer and oxygen content may drop. But then you also are
> ...


Good post!

Regarding oxygenation, everything a canister does a wet/dry does, EXCEPT the wet/dry doesn't steal O2 from the water for nitrification (as happens inside a canister). A W/D uses atmospheric O2, not dissolved O2 for the most part in the trickle tower.

A W/D skims the surface of the main tank (improving O2 exchange there); exposes the drain water to air in the overflow chamber and in the drain itself, adds O2 aggressively in the trickle tower, has more O2 exchange in the sump itself, and returns the water in a manner which agitates the surface (as does a canister also).

W/Ds clearly are better oxygenators and degassers (the main reason planted tank enthusiasts don't use them much), but that doesn't mean they are better filters per se. I have seen riverine fish benefit from their use versus canisters though.


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## lloyd (Aug 24, 2005)

further details (albeit, slightly immature) on nature's role on oxygenation: http://www.grc.nasa.gov/WWW/K-12/fenlew ... ality.html

chc: from the various information i have read, on the topic of oxygenation, it is becoming fair to assume filtration has no capacity to compliment it's process at all--wet dry included. bacteria would die, of exposure to atmosphere, long before they could breath oxygen from it. also... their notorious tag, as a 'nitrate factory' is proven. you cannot build nitrates, and increase oxygen levels, in the same process. one defeats the other. IMHO.
a few consistent factors that seem relevant to us: 1) temperature is relative, so tanked inhabitants that require higher temperatures may benefit from photosynthesis, and will benefit from additions of new water, 2) bacteria compete for oxygen, so a well maintained aquarium has benefits, as would the elimination of areas capable of trapping decaying matter (deep substrate, excessive mechanical collection materials, etc.) fish population is also relevant, so the additions of more new water, for heavily stocked tanks, is also a likely requirement. 3) if river levels of d.o. can drop dramatically, with the cease of photosynthesis at night, then a fair assumption can be made that 1) the same happens in the aquarium with lights out, and 2) surface agitation, for the purpose of in taking oxygen, compliments the d.o. process less than we have assumed, and it is not likely to assist within the confines of an aquarium either. IMO, the best it can offer, is with the discharge of other gasses.
IMHO, the simplest method to predict d.o content is with a nitrate test. one should be able to safely assume, because bacteria are the largest consumers of oxygen within a tank, that high nitrate levels equals low remaining levels of o2 for fish. ironically, all this comes down to water changes, as the #1 fundamental for healthy fish keeping.


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## maddyfish (Jul 23, 2004)

I am not terribly scientific minded. But I do have something to add to this. I have a standard shaped 75 gallon tank with a 14" midas. It is filtered by an Emporer 280, and a fluval 304 canister. The fish is healthy and has has been in this tank for 3 years. Also there is an airstone placed near the center of the tank. I put it there because I like the look of the bubbles. It has been there since the tank was set up.

Back in the summer the air pump, a tetra pump, I do not know the model, quit working. I decided not to replace it. Still anyone observing the fish would have said he was fine and healthy, but I noticed a change.

Almost immediately I noticed the fish was less active, not to the point of looking sick or hovering near the surface, but just less active and less rowdy.

I bought a new air pump (Hagen 801) and reinstalled the air stone, and almost immediately the fish returned to normal.

Was there less oxygen in the water causing a change inthe fishes behavior? I don't know. Was there less water movement allowing the fish to not be as active? I don't know. Was it purely psychological on my part or on the fish's part? I don't know.


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## lloyd (Aug 24, 2005)

maddyfish said:


> Was there less oxygen in the water causing a change in the fishes behavior?


 less oxygen?...or an accumulation of other 'noxious' gasses? we can prove surface movement assists with the venting of any abundant gasses from water. but there is skepticism over (filter comparison) claims this same process can actually inject gasses into the water. pressure seems to be the 'more relevant' variant, needed to assure that oxygen does actually infuse into water, compared to the implementation of simple agitation methods. otherwise, d.o. would not reduce so rapidly with the night time stop of photosynthesis. IMO.


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## iceblue (Apr 27, 2004)

Lloyds point of doing your water changes has a lot of merit. Water loses the ability to hold d.o. as it increases in other chemical build-ups. However their may be some disagreement as to whether fish or the bacterias in your filter are the greatest consumers of oxygen. I found this article by Lenny Llambi of the Greater Cincinnati Aquarium Society on dissolved oxygen that rehashes most whats already been said. It's an interconnected series of writings that may well be worth the read for the sake of this discussion.
http://freshwater-aquarium-fish.com/ind ... &Itemid=47


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## prov356 (Sep 20, 2006)

This thread has caused me to take a critical view of my filtering systems and how they potentially 
oxygenate the water. For the record, I run one large tank with a wet/dry, two smaller tanks with 
canisters, and several other tanks with sponge filters only. All tanks have sufficient oxygen for fish 
and biofiltration. All fish are thriving.

Regarding the wet/dry, and keeping in mind that where water is exposed to air and aggitated it has the 
greatest potential to take in oxygen, here's what I noted:

Water first flows through the overflow slots and falls an inch or so into the overflow chamber. This 
water is both exposed to air and agitated as it falls into the chamber.

Water flows through the drains and crashes into the prefilter/drip plate. Turbulence is very high. Also, 
as it sits in the drip plate, it rises to no more than .5 inch or so. So again, very exposed to air and 
highly agitated.

It drains from the drip plate through literally hundreds of tiny holes. Not agitated, but very exposed to 
air. All of this happens before reaching the biomedia, so oxygen content is as high at that point as it 
can practically be.

As the water trickles over the biomedia, it forms a very thin layer of water, so as nitrifying bacteria 
use the oxygen in the water, there's no reason that that oxygen wouldn't also be replenished. It's not 
an air tight chamber, and I do use an air pump to ensure that air is constantly being pushed into the 
chamber.

As the water drips off of the last of the biomedia, it again is very exposed to air and would have an 
opportunity to take on more oxygen. There's also some agitation as it hits the water in the sump.

Here's one opportunity I'm missing though. It occurred to me that I could be using a small pump or 
powerhead to circulate and agitate the sump water before it's returned to the tank. My returns force 
water down and toward the front of the tank in order to get a rolling circulation of tank water going.

I use a powerhead in the corner of the tank to ripple the tank surface water a bit. Another opportunity 
I'm missing is the installation of a lift tube that would pull water from the lower levels of the tank. I 
also should add one in the other back corner.

No plants in my tanks at the moment, but I'm adding a couple this week. I kill plants, so it shouldn't 
be long before this isn't a factor any longer. 

Comparing all of this to my canister tanks, they take in tank water from the lower levels of the tank, 
the bacteria use what they need, and it's returned at the surface where it can take on more oxygen 
via exposure to the air and agitation of the surface. It 's that simple. Both fish and bacteria still seem 
to get all the oxygen they need.

Sponge filters simply circulate water while agitating the surface. Again, all fish and bacteria still 
seem to get all the oxygen they need.

All work fine. But after looking at the three, the wet/dry design has so many more opportunities to 
provide all of the living organisms all of the oxygen they could ever need. The design of the wet/dry 
ensures that as oxygen is used, it's quickly replenished.

Regarding the reputation of wet/dry's as nitrate factories. Applies to reef tanks where even very low 
levels of nitrate can be harmful to inhabitants. Any filter on a reef tank would be given the same 
title, whether it be a wet/dry, canister, under gravel, etc. Most often today, none are used for that 
reason. 'Nitrate factory' simply means that the filter is producing more nitrate than is good for the 
inhabitants. Wet/dry's don't do that in a freshwater system. My nitrates in my wet/dry system are 
never higher than 10ppm. My canister filtered tanks have very low nitrates as well because I open 
them and clean them regularly. The amount of nitrates produced by any filtering system is going to 
be determined by the amount of organics that it needs to process. No filter is a 'nitrate factory' if it's 
kept clean.

One of these days (soon, I think) I'm going to get a DO meter and test the levels in each tank at 
various places to see if there's really any appreciable difference. I'm already overextended on my 
hobby budget though. 

Even after that, the question remains, what level do the fish really need, and is more than they need 
really better, or just more? Would we be healthier if we strapped on an oxygen tank and walked 
around with that all day? Don't know. Any links out there to studies done on meeting requirements 
vs providing more?

Sorry for the wordy post, but I pondered this all weekend.


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## lloyd (Aug 24, 2005)

a good post, with many interesting 'points to ponder', Tim. 
my hypothesis: oxygen is no different than any other gas, in the sense that it will attempt to equalize from one media to another, if given opportunity. the assumption, that water agitation assures oxygen intake, might only be correct, if the atmosphere (at water surface) holds more o2 than the water in contact with it. for example: photosynthesis has been noted to bring water to saturation points at day, but night time allows a rapid depletion to occur. so....is that build up of o2 consumed by inhabitants? or is excess o2 depleted/wasted by our agitation devices into atmosphere?
ironic that items installed to correct an issue, might also be involved with reversing all/any benefit, depending on time of day....we might be better to scrutinize ventilation issues, in and around our tank/open air filtration devices, than to focus on agitation alone. 
on a side note: i use the term 'nitrate factory, for wet/dry devices, on the assumption the design invites colonization within the unit, over any other surface within the tank. of course, a tank will only sustain as much colonization as needed, but like any living organism, they migrate to locations that suit their needs best. colonization is likely to occur where o2 is best sourced, and that may not be anywhere near we assume it to be. but that's another issue, worth further consideration, to those experiencing spikes during/after maintenance.


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## lloyd (Aug 24, 2005)

so now i'm staring at one of my tropheus tanks, with glass lids and full canopy, wondering if they are being choked by my desire for aesthetics and evaporation control... :lol: :? :lol:


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## prov356 (Sep 20, 2006)

> .we might be better to scrutinize ventilation issues, in and around our tank/open air filtration devices, than to focus on agitation alone.


It's an interesting point. When I set up my wet/dry with the air pump part of me felt like it was overkill and 
silly. Now I'm feeling maybe I was smart and didn't know it.  Of course before I pat myself on the 
back too much, I should go and check to see if it's really doing anything anymore, since I haven't 
checked it since I put it together. 

Regarding the amount of o2 that water can hold, that's exactly why I'd like to test at different points . If the 
water takes in all it can at point A, then the point that it has potential intake points B, C, and D becomes 
moot.


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## iceblue (Apr 27, 2004)

:lol:


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## BenHugs (Jan 13, 2007)

A quick side question on this topic. If I had a floating plant like duckweed or something similar will it help with, hinder, or do nothing for the D O???? (I'm guessing it does nothing)


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## lloyd (Aug 24, 2005)

BenHugs said:


> A quick side question on this topic. If I had a floating plant like duckweed or something similar will it help with, hinder, or do nothing for the D O???? (I'm guessing it does nothing)


 from what i have gathered, the plant will compliment oxygen production (via photosynthesis) when lights are on, and potentially help retain o2 at night (by covering/calming surface at night). the only way your live plant could interfere or hinder, would be to die off, and thereby contribute to an increase of bacterial colonization (to break down plant matter). IMO...but that seems to be changing by the page.


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## Toby_H (Apr 15, 2005)

BenHugs said:


> A quick side question on this topic. If I had a floating plant like duckweed or something similar will it help with, hinder, or do nothing for the D O???? (I'm guessing it does nothing)


floating plants have the potental to 'calm the surface'... which I would assume would discourage a gaseous exchange...

Also, from what I understand, plants will eat ammonia which would mean the need for less bacteria which needs oxygen... although I don't think this would be enough to make a difference...

And then there's the photosynthesis aspect... which is described previously better than I could do :thumb:


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## lloyd (Aug 24, 2005)

not to beat a dead seahorse, but i'm still pondering the discussion results within this thread: if oxygen content within air of the average home, measures between 8-15% , is it safe to assume we cannot exceed these numbers in our water with agitation devices alone? considering photosynthesis and diffusers as the only 'real' tools to increase d.o., and that loss occurs swiftly when either stops, has anyone considered ways to reduce this loss? would 'off' timers on agitation devices be effective at night? anyone else think that cover plants (eg. duckweed) would help? does anyone have opinion (or actually know...) that these types of surface plants help to raise/maintain d.o. content in nature? anyone else think that glass lids might defeat? compliment? or are neutral? on the topic of retaining/venting d.o. in the aquarium?


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## prov356 (Sep 20, 2006)

Just opinion, but I think the better approach is to aggressively add, rather than try to seal up and avoid 
loss. I'm not convinced that the loss occurs all that swiftly unless one has managed to saturate with 
more than what the water is able to hold, supersaturate I guess would be the word. In that case, I'm 
doubtful whether that supersaturation is really necessary, so any loss of excess wouldn't really matter. 
And you do want to provide a means of gassing off the CO2. Seal it up to retain oxygen and you also 
retain CO2. You could try to achieve some sort of equilibrium with plants, but I doubt that'd be possible 
or practical to try, and real easy to throw out of balance.

If adding O2 via plants, I think cover plants would defeat the purpose. Whatever gains would be made 
would be offset by restricting the exchange of gases at the surface.


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## BenHugs (Jan 13, 2007)

lloyd said:


> not to beat a dead seahorse, but i'm still pondering the discussion results within this thread: if oxygen content within air of the average home, measures between 8-15% , is it safe to assume we cannot exceed these numbers in our water with agitation devices alone? considering photosynthesis and diffusers as the only 'real' tools to increase d.o., and that loss occurs swiftly when either stops, has anyone considered ways to reduce this loss? would 'off' timers on agitation devices be effective at night? anyone else think that cover plants (eg. duckweed) would help? does anyone have opinion (or actually know...) that these types of surface plants help to raise/maintain d.o. content in nature? anyone else think that glass lids might defeat? compliment? or are neutral? on the topic of retaining/venting d.o. in the aquarium?


I hear that some people light up their sump tanks at night when the main tank lights are off so that photosynthesis is always part of the system.


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## b_tenant (Apr 9, 2007)

It would be interesting to compare the d.o. level in a fresh water lake to an aquarium environment. I would think that the d.o. levels would would be very low during the night just as in the aquarium. Maybe even more so because of the high level of surface area and agitation.

So is it really necessary to provide some sort of extra oxygen source during night time in your aquarium? Fish have delt with this drop in d.o. in their natural habitat for thousands of years.


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## JDS (Nov 28, 2008)

if you have the room a W/D is 10 times more efficient than any HOB filter.


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## prov356 (Sep 20, 2006)

JDS said:


> if you have the room a W/D is 10 times more efficient than any HOB filter.


Please explain. Do you mean at oxygenating water? Does that mean there's 10 times more oxygen?


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## JDS (Nov 28, 2008)

prov356 said:


> JDS said:
> 
> 
> > if you have the room a W/D is 10 times more efficient than any HOB filter.
> ...


When i said 10 times more efficient it was just a way of saying how much better the filter is. here's an example,suppose a HOB or canister filter is a flowing river.you probably have fairly decent oxygen readings.now you have to look at a W/D filter has a waterfall.which do you think we'll have higher oxygen readings out in the middle of a river or underneath the waterfall? sorry if this post sounds condescending it's not meant to be.


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## lloyd (Aug 24, 2005)

b_tenant said:


> It would be interesting to compare the d.o. level in a fresh water lake to an aquarium environment. I would think that the d.o. levels would would be very low during the night just as in the aquarium. Maybe even more so because of the high level of surface area and agitation.
> 
> So is it really necessary to provide some sort of extra oxygen source during night time in your aquarium? Fish have delt with this drop in d.o. in their natural habitat for thousands of years.


 i have read that daytime d.o. levels reach 100% (saturation) in some freshwater lakes and streams. night time loss would be restricted to an atmospheric balance. safe to assume 'good quality' night air has 20% oxygen? also, photosynthesis would have peak periods in daylight, but likely be capable of some (albeit negligible) output 24/7.
compare this to aquarium: tanks are kept indoor, often in areas (eg. basements) stifled of good air exchange. winter does not help, with fireplace/furnace competing for oxygen content. most life capable of photosynthesis are 'scraped off' weekly, and 'lights out' = total darkness. add to that, the likelihood of a dense population kept within an aquarium, the difficulty keepers have enticing certain species to breed, constant fry dieing off for 'unknown reasons', stunted or slow growths....and all of a sudden you are considering d.o. contents, etc...as potentially relevant to (lack of) success. HTH, IMHO.


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## lloyd (Aug 24, 2005)

JDS said:


> ...which do you think we'll have higher oxygen readings out in the middle of a river or underneath the waterfall?


 it depends, very much, on the oxygen content of the air your water is falling within, and the content of d.o. your falling water has to start with. falling water cannot 'sponge' oxygen from the atmosphere. it will constantly intake/exhaust in an attempt to achieve equal balance. if your water body is not producing oxygen, via photosynthesis for example, then the best you can achieve via agitation, is equal to atmosphere, whatever that might be within the area your tank is placed. HTH.


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## prov356 (Sep 20, 2006)

> and all of a sudden you are considering d.o. contents, etc...as potentially relevant to (lack of) success. HTH, IMHO.


I think you may be right about lack of DO possibly being responsible for mysterious deaths. Particularly 
the death of the largest fish in the tank, since he'd require more oxygen. I've been finding some 
interesting reading on the Internet, but nothing backed up with references to studies yet.

Here's one of the more interesting articles regarding oxygen as it relates to KOI ponds.

I should have put that DO meter on my Christmas list. :x Too late.


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## JDS (Nov 28, 2008)

lloyd said:


> JDS said:
> 
> 
> > ...which do you think we'll have higher oxygen readings out in the middle of a river or underneath the waterfall?
> ...


 I was just trying to make a simple analogy on the comparison of a wet/ dry vs.a HOB or canister filter. no offense but you seem to be over complicating it. where in your home is the oxygen content going to be lower than the water?


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## JDS (Nov 28, 2008)

http://www.aquaristsonline.com/blog/aqu ... le-filter/


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## boredatwork (Sep 14, 2007)

I have been keeping tabs on this discussion. Aside from the wet/dry vs. cannister dribble it has been interesting. I have enjoyed most of the article links.

But I am still not convinced that low levels of D.O. in the average aquarium is a real problem. While I certainly don't think convincing me is necessary, I just figured I would put my opinion out there.


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## JDS (Nov 28, 2008)

boredatwork said:


> I have been keeping tabs on this discussion. Aside from the wet/dry vs. cannister dribble it has been interesting. I have enjoyed most of the article links.
> 
> But I am still not convinced that low levels of D.O. in the average aquarium is a real problem. While I certainly don't think convincing me is necessary, I just figured I would put my opinion out there.


 the problem is everything as a reason. low D.O.could be a sign of a bigger problem. dirty water can lower the D.O. in your tank.which will also make it very difficult to control your pH. Your fish could be stressed because of possible dirty water.which is also causing the D.O.to drop which is stressing the finish.which is fluctuating your pH which is stressing the finish.


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## lloyd (Aug 24, 2005)

JDS said:


> ...where in your home is the oxygen content going to be lower than the water?


 likely nowhere, which is why agitation helps. but what if we want more? some species of fish experience saturation levels of d.o. every day.


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## JDS (Nov 28, 2008)

lloyd said:


> JDS said:
> 
> 
> > ...where in your home is the oxygen content going to be lower than the water?
> ...


 how much more do you want? what species of fish are you keeping that you need all of this D.O. if people are having problems keeping adequate D.O. saturation, for any aquarium fish I know of. Need to take a look at their tank husbandry skills.


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## BenHugs (Jan 13, 2007)

JDS said:


> lloyd said:
> 
> 
> > JDS said:
> ...


How much do I want.......all of it  I'm the guy who posted earlier about killing fish off. I did everything I knew as being right because I read every article on this site and more. My water was at near perfect levels in every way I knew to measure. My husbandry skills were at the best they had ever been. One day I overfilled the tank and my 3 fluval 405s could not keep enough 02 in my 150g tank. I lost half my stock in less than 8hrs. I have a wet dry system now and will never look back. I wish D O was talked about more :fish:


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## JDS (Nov 28, 2008)

BenHugs said:


> JDS said:
> 
> 
> > lloyd said:
> ...


 what do me you overfilled the tank?


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## lloyd (Aug 24, 2005)

JDS said:


> how much more do you want? what species of fish are you keeping that you need all of this D.O...


 IMO, it makes sense to aim for saturation levels in every tank, every day. it's part of achieving a more complete filtration system.


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## JDS (Nov 28, 2008)

lloyd said:


> JDS said:
> 
> 
> > how much more do you want? what species of fish are you keeping that you need all of this D.O...
> ...


 that's why I recommend the wet/dry filter. For oxygen saturation it can't be beet.


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## BenHugs (Jan 13, 2007)

What did I do to overfill the tank and kill half my stock.....well...
Without any knowledge of how much surface area you really need to promote the gas exchange I would fill my tank until the center brace was just under water so that my plecos would eat the algae. I would lower the water back down the next day because I never liked the look of the brace being under water. Doing this would also reduce the amount of surface agitation from the 3 fuval 405s........Now I know


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## boredatwork (Sep 14, 2007)

JDS said:


> the problem is everything as a reason. low D.O.could be a sign of a bigger problem. dirty water can lower the D.O. in your tank.which will also make it very difficult to control your pH. Your fish could be stressed because of possible dirty water.which is also causing the D.O.to drop which is stressing the finish.which is fluctuating your pH which is stressing the finish.


Not exactly sure what the means?



JDS said:


> how much more do you want? what species of fish are you keeping that you need all of this D.O. if people are having problems keeping adequate D.O. saturation, for any aquarium fish I know of. Need to take a look at their tank husbandry skills.


That is similar to the point I was trying to make. I am not convinced that there is a real problem with D.O. To me it seems like there is a frenzy of posts talking about this "problem". Now I want to make it clear that I am not disagreeing with the points being made about increasing D.O. in the tank. I am on board with all of that. I am just don't see the discussion stemming from any known problem with D.O.

In other words solutions are being present on how to hypothetically increase D.O. I think some of the points JDS makes are very important. From all of the actual "science" in the articles posted it seems like D.O. is a results of a functioning tank. It does not seem to me that it is something that can be added in. Of course if you put a tank in a vacuum, or sealed off the top, I would agree that you _might_ have a problem, but why would you do something like that?

To me it seems like if you have a problem with D.O. (which it seems like you cant even know for sure) then most likely something else is going one. So addressing the D.O. "problem" is probably not the best solution.

So again, outside of strange setups or mishaps, how many people are suspecting that they have a problem with D.O.? And more importantly, why?


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## lloyd (Aug 24, 2005)

boredatwork said:


> ....how many people are suspecting that they have a problem with D.O.? And more importantly, why?


 consider: 1) a healthy aquatic environment should seldom experience d.o. content less than 80%, 2) most fish die in d.o. content less than 30% (aka 'hypoxic'), 3) the preference for substrate in freshwater tanks invites anaerobic activity, 4) plants (either intentionally planted or pest algae types) are 'double edged swords' via complimenting to d.o. with photosynthesis in light, but continue to consume oxygen in dark, 5) a die off of anything, either intentional (algone, kill-a- snail, etc..) or accidental (missing fish in rocks, insufficient dechlorinator, filter left off after cleaning, etc..) invites immediate bacterial colonization (via decomposition) adding further demand on oxygen availability, 6) contained water, with d.o. at saturation levels, can be depleted to zero within seconds of disturbing an anaerobic cavity, 7) technological advances with oxygen injection systems have been utilized to recover fish/invert species of many worldwide canals, rivers, lakes subjected to years of pollution abuse. and in particular to our concern here, areas where water was deprived movement (due to diverted volumes) and/or excessive turbidity, 8) many aquatic species rely instinctively on areas/cold water currents for preferred migration routes, breeding grounds, etc... and d.o. levels are proven to be significant in those areas, 9) fish farms are attentive to d.o. content for their livestock, 10) i consider it overlooked in the hobby, and assume it to be relevant to many fish deaths. IMHO.


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## JDS (Nov 28, 2008)

a tank that's been properly taking care of will never have D.O.depletion to the extent that it will kill all the fish. everything you've mentioned besides the plants will cause a mini cycle. you can inject all the air you want into the tank.but that will not fix the ammonia and nitrite spike. that is what will kill your fish.


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## prov356 (Sep 20, 2006)

> i consider it overlooked in the hobby, and assume it to be relevant to many fish deaths.


I think it's definitely worth exploring. I know there are others that don't, so please don't tell me again.
There's no harm and no cost so, let us foolishly press on.


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## lloyd (Aug 24, 2005)

JDS said:


> a tank that's been properly taking care of will never have D.O.depletion to the extent that it will kill all the fish. everything you've mentioned besides the plants will cause a mini cycle. you can inject all the air you want into the tank.but that will not fix the ammonia and nitrite spike. that is what will kill your fish.


 come on... :roll: ...both ammonia and nitrite spike are linked directly to d.o. content. and so is ph stability. yes, you might try to avoid these issues by cleaning 24/7, but that leaves the tank in a precarious situation, relying on new water to 'magically' balance everything each time you do maintenance. this ignorance only leads to "do bigger water changes to solve everything". 
one assumption, that i stated earlier, may be in err. apparently, agitation alone, has the capacity to increase d.o. content to saturation levels. however, saturation levels may not be achieved in aquarium, if nitrate is allowed to accumulate simultaneously.


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## JDS (Nov 28, 2008)

if you provide proper maintenance on your tank.and you follow some basic rules which everybody who keeps fish should already know. don't overfeed, regular water changes,don't overstock your tank and have adequate filtration for the creatures you have.you will never have a problem with the the amount of dissolved oxygen in your tank. the reason why this subject hasn't been talked a lot about is because it so easily avoided.

now if you want to sit there and blame depleted levels of D.O. for the loss of your fish.because you choose to push the envelope that your problem not mine.I've learned enough in 30 years of keeping fish not to worry about.

just out of curiosity I did a search and I'm not to surprised what I found. this is just one link out of 1000 that will tell you same thing.

http://www.aquarticles.com/articles/man ... ater5.html


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## iceblue (Apr 27, 2004)

I posted the same link on page 4 and agree that all the things we already do for the health of our fish such as good filtration, proper maintenance of said filters including the cleaning of mechanical material and in my case large water changes to get rid of nitrates and dissolved organics all contribute to a better environment for oxygen exchange.

I would say one of the reasons you find so little information on the subject is that it's never been a problem for most fish keepers and is more a curiosity then something we need to be worried about.

It's still a good thread though. :thumb:


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## JDS (Nov 28, 2008)

iceblue said:


> I posted the same link on page 4 and agree that all the things we already do for the health of our fish such as good filtration, proper maintenance of said filters including the cleaning of mechanical material and in my case large water changes to get rid of nitrates and dissolved organics all contribute to a better environment for oxygen exchange.
> 
> I would say one of the reasons you find so little information on the subject is that it's never been a problem for most fish keepers and is more a curiosity then something we need to be worried about.
> 
> It's still a good thread though. :thumb:


 YUP.


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## Number6 (Mar 13, 2003)

JDS said:


> if you provide proper maintenance on your tank.and you follow some basic rules which everybody who keeps fish should already know. don't overfeed, regular water changes,don't overstock your tank and have adequate filtration for the creatures you have.you will never have a problem with the the amount of dissolved oxygen in your tank. the reason why this subject hasn't been talked a lot about is because it so easily avoided.


Strongly disagree!

There must be reasons why experienced cichlid keepers can keep Oscars, Discus, apistos, mbuna and haps with 100% success yet they cannot succeed with Zebra Plecos, Cyps, Sand sifters and the like which are all species that I have found to be very intolerant of low O2 levels.

I strongly suspect that fish like Zebra plecos are such a problematic little pet because they really want oxygen levels higher than the average modern house will afford them.

I'd like to see this discussion continue... 
I like this article as a good problem statement: 
http://edis.ifas.ufl.edu/pdffiles/FA/FA00200.pdf

and I like this article for some backup that low O2 for some species starts to stress them long before many visible symptoms!

I'm glad to see some hobbyists checking out the situation, and I strongly resent your (not so subtle) accusation that Lloyd or others are overstocking or whatever you meant by "pushing the envelope".

If you don't feel a need to explore this topic, then great... bow out.

Lloyd, Prov, I am interested to see what else you dig up on this topic. 
:thumb:

http://www.holar.is/helgi/vatnsfraedi/surefnismang.pdf


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## lloyd (Aug 24, 2005)

thank you #6. after 6 pages of (mostly) useful dialogue, i was beginning to worry this topic would close with another 'it's all your fault for not knowing better...so why talk about it'.
here's a few things i have picked up so far:
1) temperature is relative to d.o. content. higher temps retain less of it, so species requiring higher temperatures, those who increase temperature for breeding conditioning, or remedies assisted with increasing temp (eg. ick) require attention to oxygen levels.
2) agitation alone cannot assure d.o. content. ventilation is also necessary. tightly fitted lids/canopies will deter good gas exchange. 
3) hobs may loose the popular vote over sump type systems, but a hob delivering good surface roll, on a tank allowed ventilation areas around glass lids, is capable of delivering. 
3) salinity levels are relative, as in more salt=less d.o. again, this is important for remedies involving salt, but also important for those keeping brackish species, and for those who include salt in their parameter adjustment mixes (eg. rift lake recipes).
4) water depth is relevant in nature, as in deep water has less d.o. content, but a few inches in aquarium is likely irrelevant. it is still worthy of note, for those keeping species demanding high d.o. content, than upper levels hold the majority of d.o. content. assuring good water movement, throughout the entire tank, is a good set up consideration for any tank. power heads are an important tool, too often overlooked by new hobbyists in particular.
5) bacteria are a major consumer of oxygen. although we need to tolerate certain bacteria, for cycling issues, detritus must be minimized to reduce decomposition issues within substrates and filter media.
6) oxygen depletion can occur rapidly when conditions allow. power outages, moving fish in pails/bags, extended periods of darkness, are just a few examples of time for concern. 
7) photosynthesis is a major producer of d.o. content. plants are a welcome consideration to any tank, as well as tolerance for green algae, to assure good content. but the timing for light exposures on/off does become relevant, as all greens consume oxygen at night.
eight) water changes alone cannot assure d.o. saturation levels. but water changes do remove other accumulations, that compete for oxygen within water, so it is an important part of assuring good d.o. content.
9) more fish=more demand for oxygen. this is a logical consideration, when stocking species demanding high d.o., but might be overlooked by keepers who insist on overstocking their tanks. especially, during power outages, for example.
10) toxic levels (hypoxia) can occur quickly if anaerobic areas are disturbed. removing fish, before removing/changing substrates, is likely a good precaution. also, when siphoning, leave the nozzle in gravel until water runs clear before moving to the next area. removal is key. simply 'stirring things up' is dangerous.


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## JDS (Nov 28, 2008)

Number6 said:


> JDS said:
> 
> 
> > if you provide proper maintenance on your tank.and you follow some basic rules which everybody who keeps fish should already know. don't overfeed, regular water changes,don't overstock your tank and have adequate filtration for the creatures you have.you will never have a problem with the the amount of dissolved oxygen in your tank. the reason why this subject hasn't been talked a lot about is because it so easily avoided.
> ...


 I'm not arguing the fact that certain species need more oxygen than others. what I am arguing is that depleted levels of dissolved oxygen in the water are the end product of a something else. LLOYD keeps posting what causes oxygen depletion and for some reason wont's to fix the end result instead of what's causing it.

here's an article that should better explain what's happening with people that have a lot of sand in their tank and/or deep gravel substrate. I would assume this is what's happening with people that have fish that like to dig everywhere in the Sand.

http://reefkeeping.com/issues/2005-12/rhf/index.php#14


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## JDS (Nov 28, 2008)

and yes has a previous poster mentioned before I'm on those closed minded reefers. 

but in all seriously if you want to find out interesting information about water chemistry lighting filtration do-it-yourself projects this site has more information than you will ever need.

http://www.reefcentral.com/forums/index ... 988754d2ef


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## JDS (Nov 28, 2008)

one other thing to think of, if D.O is a big problem then why isn't that thousands of Americans keep North American fish. some of these fish meat or exceed oxygen needs of there tropical counterparts?


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## Number6 (Mar 13, 2003)

JDS said:


> one other thing to think of, if D.O is a big problem then why isn't that thousands of Americans keep North American fish. some of these fish meat or exceed oxygen needs of there tropical counterparts?


Funny you mention this as I've often tried to keep fish like brook trout that seem to be low DO intolerant (sunfish and bass are low DO tolerant IME) and they always fail... even when I've tried to mimic everything possible in articles. The only thing left that I felt like trying one day was to try a planted sump on a reverse schedule to keep DO levels extra high at all times.

Now in my cichlid keeping experience, I have long blamed low O2 levels on cichlid fans failures with Cyps... especially when the cyps die for no apparent reason overnight (often with that arched back and gaping mouth). I'm often ridiculed, because what I suggest makes no sense to the OP. How can healthy fit fish die off one by one at night time and no one has ever heard of this "supposed" illness?

Well, I think we all have heard of it...

So, I've tried better filters, HOB, wet drys, etc. and time and time again, I find them all lacking in avoiding mystery deaths.

After implementing planted sumps, airstones in all tanks, and opening windows to my house once in a while, no more mystery deaths in my tanks... or at least hardly ever.

Are you sure Lloyd cannot possibly have a worthwhile path of investigation? It sure sounds like it makes sense... setting up a perfect tank, adding HOB filters, and all looks great might make one think all is sound, but what if we are all a HOB motor shutting off away from a tank full of dead fish because nobody has ever considered if there were simple ways to ensure PLENTY of O2 in the water? Imagine if something as simple as a capful of H2O2 into a fish tank in the evening could avoid deaths for fish keepers...

isn't that worth finding out?


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## JDS (Nov 28, 2008)

Let me clarify myself. I'm not saying low levels of DO will not kill your fish of course it will. What I'm saying is low DO levels are an end result of something else. Nine times out of 10 it's a symptom not a cause. So in my thinking if you eliminate the cause you won't have the symptom. Dissolved oxygen just doesn't disappear from your tank. Something makes it disappear.


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## lloyd (Aug 24, 2005)

JDS said:


> Let me clarify myself....Dissolved oxygen just doesn't disappear from your tank. Something makes it disappear.


 do you even read others posts? :? i just listed 10 potentials relevant to varying d.o. levels. avoid, and/or implement, any/all of them into your system, and d.o. content should no longer be an issue for concern.


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## JDS (Nov 28, 2008)

lloyd said:


> JDS said:
> 
> 
> > Let me clarify myself....Dissolved oxygen just doesn't disappear from your tank. Something makes it disappear.
> ...


 yes I do read other posts including yours. Which is why I stated proper maintenance and you won't have this discussion. But the minute you gave me one of these. :roll: you marginalize yourself in my eyes.


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## Number6 (Mar 13, 2003)

JDS said:


> Nine times out of 10 it's a symptom not a cause. So in my thinking if you eliminate the cause you won't have the symptom. Dissolved oxygen just doesn't disappear from your tank. Something makes it disappear.


Yes, agreed. Now what I want to hear discussed is that single out of ten. 

Dissolved oxygen is used up in a normal functioning aquarium (and has to be), but my curiosity is piqued about the possibilities that normal usage could eat up more O2 than a particular cichlid species is very prepared to handle.


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## lloyd (Aug 24, 2005)

"But the minute you gave me one of these... :roll: ...you marginalize yourself in my eyes"

:roll:


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## JDS (Nov 28, 2008)

Number6 said:


> JDS said:
> 
> 
> > Nine times out of 10 it's a symptom not a cause. So in my thinking if you eliminate the cause you won't have the symptom. Dissolved oxygen just doesn't disappear from your tank. Something makes it disappear.
> ...


 sorry the only advice I can give you hear is don't be that one of the 10. :wink:


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## JDS (Nov 28, 2008)

lloyd said:


> "But the minute you gave me one of these... :roll: ...you marginalize yourself in my eyes"
> 
> :roll:


 :wink:


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## lloyd (Aug 24, 2005)

here's another interesting article: http://waterontheweb.org/under/waterquality/oxygen.html

i noted how lower d.o. levels, affect embryo development and early life stage development of salmon, other fish and invertebrates, in a negative way, right across the board. varying levels of affect, from species to species, but a notable affect to all regardless. HTH.
it's noted remarks, about ice cover affecting d.o. content, strengthen my opinion glass covers may hinder same within aquariums. IMHO.


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## JDS (Nov 28, 2008)

lloyd said:


> here's another interesting article: http://waterontheweb.org/under/waterquality/oxygen.html
> 
> i noted how lower d.o. levels, affect embryo development and early life stage development of salmon, other fish and invertebrates, in a negative way, right across the board. varying levels of affect, from species to species, but a notable affect to all regardless. HTH.
> it's noted remarks, about ice cover affecting d.o. content, strengthen my opinion glass covers may hinder same within aquariums. IMHO.


 glass tops make a wonderful gas exchange blocker. You could always try plastic egg crates cut to fit over your tank. You can buy these at any home improvement store they're like a grillwork for fluorescent lighting.http://www.eplastics.com/Plastic/Lighting
This also prevents your fish from being able to jump out. I have to have my tanks covered. If I didn't it be like a rain forest in my house. And I don't feel like having the added expense of running a dehumidifier 24 /7.


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## BenHugs (Jan 13, 2007)

I would like to add to this topic. If a tight fitting lid reduces gas exchange but without one I would have major evaporation issues. Is there any way to prevent evaporation (keep it to a minimum) but still allow plenty of gas exchanging.


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## lloyd (Aug 24, 2005)

BenHugs said:


> I would like to add to this topic. If a tight fitting lid reduces gas exchange but without one I would have major evaporation issues. Is there any way to prevent evaporation (keep it to a minimum) but still allow plenty of gas exchanging.


 i'm considering to vent the area with an airline tube. one idea, is to import room air, with a spare line from my blower, aimed directly over the water. this should assist plenty with air exchange within that enclosed area, as there is plenty of small openings around the rear hob area for escape. or, utilize the venturi of a power head, which draws air into it's water volume. with this idea, i want to assure the tube is long enough, to source air from outside the enclosed area. this might be difficult with some smaller power head, as any pump's venturi draw capacity is limited by height and distance of tubing.
the first idea benefits species requiring calm, quiet waters. the latter would be fine for my stingray, pleco, etc, which appear to need/enjoy the bubbles of venturi/sponge filter type injectors anyway. covering these tanks, would help me with evaporation and daily 'top up the sump' time, so i will start cutting glass this weekend.  i just wish i had a way to measure success, if any occurs at all.  
both ideas leave glass lids intact, to continue restriction of evaporation. the down side predicted, if gas exchange is improved, would be an increase of algae growth on the underside of glass. HTH.


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## boredatwork (Sep 14, 2007)

I'm really confused over the last 10 or so posts.

I don't know about anyone else but I am not saying I don't think the discussion is useful.

More importantly, I don't think anyone has said that water low in oxygen is not a bad thing. Obviously water low in oxygen is a bad thing. The question I still have is why are so many people saying this is a problem in this hobby?

I am not even saying it is not a problem, I am just interested in why there is such a firestorm of posts over this topic. I have not seen anything stated to say that there should be a concern over it. Obviously water low in oxygen is a bad thing. I am not asking why water low in oxygen is a bad thing, I am asking why people think they have a problem with water that is low in oxygen?

I'm crossing my fingers that I said it enough ways to be clear, haha.


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## JDS (Nov 28, 2008)

boredatwork said:


> I'm really confused over the last 10 or so posts.
> 
> I don't know about anyone else but I am not saying I don't think the discussion is useful.
> 
> ...


as I stated before I don't think it is a big problem for the majority of people that follow some basic steps in fish keeping. There's been a lot of things posted in this thread about certain preventative measures that you can take to prevent it. Follow these measures and it's not going to become a problem. But that is just my humble opinion. Based on many years of keeping all types of fish.


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## smellsfishy1 (May 29, 2008)

I am going to kinda jump in here but I have followed this thread carefully to date.
I would like to say that everything stated by all has been important to the thread.
It all is relative to one another so I consider all of it important to the subject of D.O.
Whether it is a cause, effect, solution, or function everything has been beneficial.
Especially the links and some of the more detailed scientific explanations. Maybe because I am a chemistry major.


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## JDS (Nov 28, 2008)

smellsfishy1 said:


> I am going to kinda jump in here but I have followed this thread carefully to date.
> I would like to say that everything stated by all has been important to the thread.
> It all is relative to one another so I consider all of it important to the subject of D.O.
> Whether it is a cause, effect, solution, or function everything has been beneficial.
> Especially the links and some of the more detailed scientific explanations. Maybe because I am a chemistry major.


 I'm glad you find some of these long drawn out papers interesting. I start reading them and keep wondering when they're going to speak English again.


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## prov356 (Sep 20, 2006)

It's not a major problem in aquarium keeping. Those have all been addressed pretty well. So, 
when something like this comes along that *may *be a problem with certain fish, it can be 
intriguing to explore it.

It also could be something that is more of a problem than we realize. Maybe 'problem' is 
strong. Fish can live for quite a while and seem to do ok in high levels of nitrate, but we know 
now via studies that have been done that certain levels can have long term negative effects on 
fish. Oxygen may be the same.

We may find ways to fine tune our systems so that fish that are sensitive to lowered oxygen 
levels are no longer exposed to same. We may also learn some surprising things about our 
filter systems and how well they oxygenate the water. We may explode some myths, and/or 
confirm others.

I don't see the posts the way you do. I don't see everyone here jumping up and down and 
waving their arms over the serious oxygen problem in aquarium keeping. I think what you see 
instead are just emotional responses to other emotional posts. And that makes it appear that 
the issue is being elevated by some when it's really not.

I am sort of amazed at how some that think this isn't worth the time can't just walk away. 
From my seat it appears that we have some that have decided that this isn't worth *anyone's *
time and would just like to see the thread die. I see the thread getting seriously sidetracked 
wasting time defending it's existence instead of moving ahead.

When we all put our collective knowledge and experience together and aren't afraid to ask 
'what if' and 'is it possible that maybe we can do this better', then I think a forum like this 
reaches it's full potential. Too often these types of threads get killed when we're all told to get 
our minds back in line with the community 'group think'. I've seen it too often. And you know 
it's true. Suggest something that goes against the mainstream and risk being seriously flamed.

Some seemingly ridiculous ideas or suggestions can spawn off other ideas and lead to useful 
things. It's ok to just kick stuff around and see what turns up.

One last thought and I'll be done. I think there are a couple of different camps when it comes 
to aquarium keeping. Some are into the details and some are not. The ones that aren't 
really have a difficult time understanding the ones that are. Those details seem like a waste of 
time and effort. To some, like myself, it's part of the fun of the hobby knowing the details even 
if that's not a necessary part of successful aquarium keeping. It's the fascinating, fun stuff to 
me.

I broke down and ordered a DO meter today and am looking forward to taking some readings.
It may turn up nothing useful, but I'll enjoy doing it all the same. It's just a hobby and we can 
all take it wherever we want. That's part of what I like about it. You can go a lot of different 
directions with it.

HTH


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## lloyd (Aug 24, 2005)

boredatwork said:


> I am asking why people think they have a problem with water that is low in oxygen?


 for me, it has to do with increased success to breed certain species, increasing the survival ratio of embryo to fry, and in the rare tank, success to simply keep certain species alive long term. 
maintaining sufficient oxygen in water sounds like a nobrainer. guys like jds, for example, rely on the fact, that 20% atmospheric content is plenty to assure saturation in water, because water saturates at a much lower percent. simple science.
guys like me, sense something is missing in that assumption. too many fish (embryo, fry in particular), die for unexplained reasons. too many fish do not breed in aquariums at all. many keepers realize these issues, but we stop short of pursuing discovery, and simply tag those species as 'too difficult' to keep. success is in the details, IMO, and i relish the challenge to breed what others can barely keep alive. want pictures to prove success?









that's one tank of moba babies..i have 3 more.


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## gherlevi (Dec 16, 2004)

Prov, you bought a meter?!?! Holy heck.

Please share your results, whatever you study! I've seen enough of your posts to know that your methods will be methodical and informative.


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## Number6 (Mar 13, 2003)

boredatwork said:


> I'm crossing my fingers that I said it enough ways to be clear, haha.


Not me; someone else- young Cyps, found dead in morning, arched back, open mouth. Fish appear healthy in every way shape and form prior to showing up dead. Sounds a bit like a DO problem despite "more than adequate" filtration on the tank. I'd even say it's overfiltered!

I'm open to investigating anything else worth looking into... but right now, I suspect a O2 problem. :thumb:


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## JDS (Nov 28, 2008)

lloyd said:


> boredatwork said:
> 
> 
> > I am asking why people think they have a problem with water that is low in oxygen?
> ...


 you have to come over to the salty side. I'm sure your appetite for a challenge could easily be met. :wink:


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## JDS (Nov 28, 2008)

prov356 said:


> It's not a major problem in aquarium keeping. Those have all been addressed pretty well. So,
> when something like this comes along that *may *be a problem with certain fish, it can be
> intriguing to explore it.
> 
> ...


 don't worry I'm done posting on this subject nothing more I can really add. continuing on would only be looking for ghosts. :thumb:


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## iceblue (Apr 27, 2004)

prov356 said:


> I broke down and ordered a DO meter today and am looking forward to taking some readings.
> It may turn up nothing useful, but I'll enjoy doing it all the same. It's just a hobby and we can
> all take it wherever we want. That's part of what I like about it. You can go a lot of different
> directions with it.
> ...


Very cool. Kudos to you Prov. :thumb: I'm glad to see the thread going in this direction.

I found this chart looking around for "dissolved oxygen in the home aquarium" on the net. It gives a baseline maximum of dissolved oxygen in water of varying hardness and temperatures. I can't vouch for it's accuracy but it should make a good baseline for comparison.

http://www.algone.com/oxygen.php


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## boredatwork (Sep 14, 2007)

iceblue said:


> 'm glad to see the thread going in this direction.


I'd have to second that.

Tim, I don't know if you were referring to my probably annoying posts, but I hope I didn't convey that I think this discussion is silly or pointless, or that I want it to end. Quite the contrary. I feel like I have said several times that I do think this is an important discussion.

But I still feel like I have a question. For lloyd and Number6, or anyone for that matter, what has led you to believe that the problems/challenges you are describing are oxygen related? I understand the issues that have been raised, and I understand the want/need to have the best possible aquatic environment, but what is the connection to D.O. Is it just a (educated) guess?

I ask this not to shutdown the discussion but to find the logical starting point. I think that in this hobby there is an extremely false sense of complete knowledge. In other words I would say that there are ton of things that we do not know about when it comes to fish and their habitat, let alone recreating it. This is especially true in freshwater aquatics. Even a comparison to the saltwater people shows that they tend to know more and do more to create a theoretically perfect environment. In my opinion its not hard to see that the saltwater hobby is more advanced than freshwater hobby. Go read a saltwater forum for a few weeks and I think this becomes obvious - or at least it was to me. In other words, I think there are million things that we should or could do in this hobby to be better custodians of these creatures - measuring D.O. could be one of them. But in general most people feed their fish, do an occasional water change, and leave it at that. When it comes to water, environment, and fish behavior there are so many combinations of things that we could care about. The average person has pretty much zero knowledge, or even awareness of all of those "factors", and certainly there is always some debate over whether these things matter.

In light of this when we try to do a better job, sometimes we come up with some random parameter to try and fix, which I always find interesting, because how of all of the possible things to be concerned about, did this person end up with this random thought, as if they fix 1/1000 instead of 0/1000 parameters things will be better. I am not saying it won't be, I am just saying sometimes, to me, these things seems kind of random and illogical. And again, random and illogical does not necessarily invalidate any benefit that is realized. I really want to stress that. But random and illogical can easily be made intentional and logical if we understand what is going on, and as a result will ultimately become more beneficial to the hobby.

So...My point is how of all the possible things that you could think of did D.O. arise as a possible solution to your concerns?


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## lloyd (Aug 24, 2005)

boredatwork said:


> ...is how of all the possible things that you could think of did D.O. arise as a possible solution to your concerns?


 i do not think of d.o. as a solution to much. it is most relevant, to realize how many reactions within an aquarium, can cause it to fluctuate. a good keeper will always strive to reduce any parameter from fluctuation, as this is well confirmed to cause stress. 
another important understanding, is the true definition of 'saturation'. the easy misunderstanding, is that saturation equals maximum d.o. content, which equals plenty of oxygen. knowing, for example, that nitrate accumulation lowers the d.o. saturation point of water, regardless of agitation/surf tools, adds a further dimension to the 'complexities of simple maintenance'. HTH.


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