# Cichlids and filtration



## psyber (Jan 7, 2009)

I have been poking around this forum for a few weeks now and I have noticed that people keep recommending at least 8-10 GPH per gallon. My question is why so much. Are cichlids just that darn messy compared to other fish (e.g. Tetras)?

Also, what are your thoughts on filters that use cartridges (e.g. tetra tech) instead of loose media (e.g. aquaclear)? Based on what I have read here, and elsewhere, I am thinking that loose media filters are superior as they can be customized to contain greater amounts of bio filtration at the expense of chemical filtration (e.g. activated carbon)? Especially considering activated carbon is only effective for a week or so while the bacteria on media can last much longer. Am I way off base here or does this make sense?

Thanks,
Psyber


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## lotsofish (Feb 28, 2008)

> Are cichlids just that darn messy compared to other fish (e.g. Tetras)?


Yes, messy but not as messy as goldfish. Also some folks that stock mbuna, like to overstock their tanks to spread out aggression.



> Am I way off base here or does this make sense?


It makes sense. Aquaclears are a favorite HOB filter on this forum for the reason you state. Personally, I like the Emperors better because they can have slide in trays that can be customized to some degree.


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## KaiserSousay (Nov 2, 2008)

> Are cichlids just that darn messy compared to other fish (e.g. Tetras)?


YES..should you get involved with these gilled poo producers, you too will be looking for the Grail, an inexpensive filter system that does it all.


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## psyber (Jan 7, 2009)

Interesting. Does anyone have numbers for comparison? For instance if a sword tail produces x grams of waste a day a typical chichlid produces y amount?


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## lotsofish (Feb 28, 2008)

I'm sure it has a lot to do with body mass. A swordtail just doesn't get very big or eat very much.


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## Ravenatnm (Mar 20, 2008)

Think about how much food you feed them. I bet they are pooping out about 80% of what they eat.


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## psyber (Jan 7, 2009)

Ravenatnm said:


> Think about how much food you feed them. I bet they are pooping out about 80% of what they eat.


So then other fish of the same size will poop less than 80% of what they eat?


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## psyber (Jan 7, 2009)

lotsofish said:


> I'm sure it has a lot to do with body mass. A swordtail just doesn't get very big or eat very much.


So then a fish the same size as an average cichlid, but not a cichlid, will produce as much waste as a cichlid and require just as much filtration?

Sorry for the annoying questions, I am just trying to understand what I am getting myself into.


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## califjewls (Dec 28, 2008)

Cichlids are not only big poopers, they are messy eaters also so that contributes to the waste load, they seem to like to chew spit chew spit chew spit some more, whereas Tetras for example just put food in their mouth and eat!

My 37 gallon turns over 13 times an hour, I still have to siphon out poop every couple days, no other type of freshwater fish that I have had (tetras, swordtails, gouramis, etc) make the mess my Mbuna do...

You want these guys and gals to have the best water conditions and when you overfilter these messy fish you have nice stable water conditions.

Just my 2 cents..


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## smitty (May 7, 2004)

I swear by aqua clear. Not only do i think they are the best filters. They are also the least expensive to operate. People have been hook winked with the bio-wheel, hype. Get aqua-clear and add some bio-max balls to colonize your bacteria. On my 180gal I am running 3-110 power filters, 1-Eheim 2260, 1 aqua clear powerhead 110. This tank has 5 dovi's that are always spawning. 
My 150gal- has also the same filtration
by the way my Eheims are 15years old with no problems


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## prov356 (Sep 20, 2006)

> So then a fish the same size as an average cichlid, but not a cichlid, will produce as much waste as a cichlid and require just as much filtration?
> 
> Sorry for the annoying questions, I am just trying to understand what I am getting myself into.


Yes, it all has to do with body mass, and not because they're cichlids. Cichlids don't require more 
'turnover' than other fish. They require clean water, but don't most fish?

8-10 times turnover isn't necessary. There's nothing magic about turnover. I can put a bunch of 
powerheads in a tank and get a lot of 'turnover' in a tank that's a toxic soup. Instead, think removal of 
organic wastes from the system. This 'turnover', if associated with filters can help in that it's more 
likely to kick the detritus into those filters where it can be easily removed, but that's the only advantage.
You can also let it settle on the substrate and vacuum it out when doing frequent partial water changes 
(my preference). If you get the detritus into the filters, but leave it there, little has been gained.

Biofiltration requires some turnover, but very little. Aerating and oxygenating the water requires some 
turnover, but again, very little. Lots of water movement doesn't necessarily mean cleaner water. It 
may just mean lots of water movement.

Bottom line, do frequent partial water changes while vacuuming the substrate. Change or clean 
mechanical filtration media to remove collected detritus. Run your tank water through your biomedia 
a few times per hour, and use a filter output to get a little surface ripple to encourage gas exchange 
at the surface. Do this and your fish will prosper, no matter what kind they are. Oh yeah, and don't 
overstock or overfeed (although a power maintenance routine can overcome this, I don't recommend 
it  ).

Your questions aren't annoying at all, keep asking, good for you. :thumb: Question everything you read.


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## psyber (Jan 7, 2009)

prov356 said:


> Yes, it all has to do with body mass, and not because they're cichlids. Cichlids don't require more
> 'turnover' than other fish. They require clean water, but don't most fish?


Thank you, this helps clear up some of my confusion.



prov356 said:


> 8-10 times turnover isn't necessary. There's nothing magic about turnover. I can put a bunch of
> powerheads in a tank and get a lot of 'turnover' in a tank that's a toxic soup. Instead, think removal of
> organic wastes from the system. This 'turnover', if associated with filters can help in that it's more
> likely to kick the detritus into those filters where it can be easily removed, but that's the only advantage.
> ...


Again, very helpful. It seems like the distinction between turnover and filtration is sometimes lost in discussions about filters.


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## prov356 (Sep 20, 2006)

> Again, very helpful. It seems like the distinction between turnover and filtration is sometimes lost in discussions about filters.


It is, it is. Too simplistic of an approach to filtration. Adding a filter and it's turnover may increase 
filtration, or it may just add a device that has to be cleaned. Now half the detritus is in one place and 
half is in the other. They may pickup more combined, true, but not necessarily. I often see 
recommendations to add filters for well-meaning, but questionable reasons. Adding another filter just 
like the one that's already on the system, doesn't necessarily 'double' filtration. Adds more biomedia, 
true, but is it needed, particularly in a mature tank where nitrifying bacteria colonize much more than 
filter media? Adds more mechanical filtration (maybe), but now instead of vacuuming substrate and 
cleaning media in one filter, you're vacuuming substrate and cleaning media in two filters. And if you're 
like me and don't like to clean filters and leave them too long, then it may actually leave detritus in the 
system longer than it would have been if you had just vacuumed it up.

Just food for thought and my .02


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## boredatwork (Sep 14, 2007)

Prov already made the point, but this is on my list of topics I just cant let go, so I will share my perspective however redundant it ends up being. I like to think my perspective is on the how and then the why.

*Filtration Basics*
Filtration provides three things in a fish tank: mechanical filtration, biological filtration, and water flow. Of these three functions one of them is essential and the other two are cosmetic.

Biological filtration is the only essential function of a filter. However, while bio filtration it is an essential function in a tank, a filter is not an essential component of biological filtration. In other words, most people use a filter to provide bio filtration, but bio filtration does not only occur in the filter. So theoretically it is possible to not even need a filter in a tank.

Mechanical filtration and water flow are not essential functions of a tank, but without them you are betting on an ugly mess for a tank.

*Sufficiency*
Taking the two most common uses of a filter, bio and mechanical filtration, there are two tests for filter sufficiency. The test for sufficient bio filtration is to have 0ppm of ammonia and 0ppm of nitrite in your tank. If you can do this without a filter, then you don't need a filter. If you currently have a filter that is keeping ammonia and nitrite at 0ppm, then you don't need any more filtration. This is the ultimate requirement for keeping fish alive. Hopefully that's not our only objective, but clearly it is the most important one.

An important note is that sufficient bio filtration is dependent on bio load. For example, if you have one fish in your tank with a filter that is keeping ammonia and nitrite at 0ppm, but then you add 100 more fish, it may not be the case that the filter will still keep ammonia and nitrite at 0ppm. By adding more fish, or as your current fish grow bigger, you may need more filtration if the current filter does not keep the ammonia and nitrite levels at 0ppm.

The test for sufficient mechanical filtration is a combination of your eyeball and your brain. If you think your tank water looks clean then you have sufficient mechanical filtration. If you think your tank water looks dirty, then you might consider increasing the mechanical filtration capability (not necessarily capacity) of your filtration system.

*Function*
The most commonly used metric to determine sufficient filtration is GPH. But really, within reason, GPH has little effect on either bio or mechanical filtration. Bio filtration is about having enough surface area to build colonies of bacteria. The established bacteria takes the ammonia out of the water and converts it to nitrate. If the filter was the only source of bacteria in the tank then GPH might be of medium concern, but in reality all that needs to occur is for the ammonia produced at any given time to be run through the filter at some moderate rate for the complete ammonia conversion. As long as the rate of ammonia consumption by the bacteria is greater than the rate of ammonia production by the bioload, then you are good to go. However, since there is no way to measure either of those rates we can only rely on anecdotal information to make our filtration decision. Again, if ammonia and nitrite are at 0ppm GPH requirements are being met.

Mechanical filtration also has only moderate dependence on GPH. If you took a big bucket of poo and dumped it in the water and wanted it cleared up quickly then you would want a high GPH filter. Other than a scenario such as that, a moderate GPH will be able to filter out waste over time. In other words, all you care about is that the rate of waste filtration is greater than the rate of waste production. Once again, there is no way to calculate waste production or waste filtration, so we rely on anecdotal evidence. However, the more important aspect of mechanical filtration is not GPH but the media itself.

*Filter Media *
There are two aspects of media - media type and media volume. When it comes to media type you need to have the right kind of media for the job. If you are trying to trap floating poo than most any coarse grain media will be sufficient. But the most common problem people run into is tiny particles floating in the water. Well, if there are tiny particles then you need media with even tinier holes to be able to trap the tiny particles. Otherwise if the pore size of the media is larger than the tiny particle, the tiny particle will just pass through the filter media. I include myself when I say as obvious as that sounds a lot of people don't always come to that revelation.

As for media volume, this is not really important for filter function. This is really only important for people who don't want to clean their filter. But as prov said, just because you can't see the waste does not mean it is not there. Believe it or not the filter is part of the water system of your tank. The waste is just as bad stuck in the filter as it is sitting on the sand in your tank. It just looks nicer in the filter because you can't see it.

*Summary*
When it comes to bio filtration all you care about is achieving 0ppm of ammonia and nitrite. If that is not happening then you need more filtration - either by adding a filter or by using more efficient bio media. GPH is of small importance to bio filtration.

When it comes to mechanical filtration all you care about is the clarity of the water. If the water is not clear then more often than not you need different media, not more media. Remember the rule: Fine media for small particles. If the filter is clogging too quickly then you can consider adding filtration but keep in mind that adding mechanical filtration means that more waste will be sitting in the water system. In my opinion you arer better off cleaning the filter once it clogs. That is the only way to actually remove the waste from the system. As an addendum to that, vacuuming the substrate will also remove waste from the system and will keep it from clogging up the filter as often. So in my opinion, vacuuming the substrate is just as essential to filtration as the filter itself.

Also remember that even though we like to think about bio and mechanical filtration as two separate things, all filter media does both. Bio media will filter out waste, and mechanical media will provide a nice haven for bacteria. So in reality (which exists outside of the marketing world) there is no such thing as "bio media" or "mechanical media". My preference is to use a media that is good at both since that will maximize total filtration efficiency

As for the one function I left out, water flow (i.e. GPH) is not a good reason to buy a filter, just get a powerhead if you need more water flow in your tank. 
[/b]


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## psyber (Jan 7, 2009)

Thanks *boredatwork*, that was very informative! Seems like you have put a lot of thought into filtration. Have you considered writing an article for the forum's [/quote]library? I think others wound find your views helpful well.


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## Maddog (Nov 7, 2008)

very informative thread!


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## prov356 (Sep 20, 2006)

> Also remember that even though we like to think about bio and mechanical filtration as two separate things, all filter media does both. Bio media will filter out waste, and mechanical media will provide a nice haven for bacteria. So in reality (which exists outside of the marketing world) there is no such thing as "bio media" or "mechanical media". My preference is to use a media that is good at both since that will maximize total filtration efficiency


True, in the real world they both do both but...

Relying on mechanical filtration pads or whatever to also do biofiltration can work, but it takes some 
managing when filter cleaning. I prefer to keep them separate, so you can aggressively clean the 
mechanical filter pads and clean them often without worrying about losing bio. The biomedia should be 
able to handle biofiltration without needing a helping hand from the mechanical media. Once the 
mechanical filter pad gets full of detritus, it's questionable how much activity there is from nitrifying 
bacteria vs. heterotrophic bacteria.

When biomedia 'filters out waste', it really is just converting it, not removing it, so doesn't qualify as 
mechanical filtration. If it's doing both, and collecting detritus, it may be to the detriment of 
biofiltration because now you have areas of reduced or no flow of oxygenated water.



> Filtration provides three things in a fish tank: mechanical filtration, biological filtration, and water flow.


And sometimes chemical filtration, don't forget that one. Not often used, but does deserve a 
mention.



> Mechanical filtration and water flow are not essential functions of a tank, but without them you are betting on an ugly mess for a tank.


If you don't remove the detritus (mechanical filtration), it will eventually overwhelm any biofiltration. 
So, I'd have to disagree and state that some form of mechanical filtration is indeed necessary.

Same with water flow. It doesn't have to be provided by a filter, but is indeed necessary unless 
you're keeping a bare minimum number of fish. Good circulation results in good oxygenation.



> If you think your tank water looks clean then you have sufficient mechanical filtration.


I like to think of mechanical filtration as complete removal from the system, whether by vacuuming 
the substrate or cleaning of the filter. It's just like the nitrogen cycle and biofiltration. Until the nitrates 
are removed (usually through dilution), the nitrogen cycle is not complete.



> GPH has little effect on either bio or mechanical filtration


The UGJ keepers might beg to differ with that one. 

Not trying to pick apart your info, it was well done. Just offering some points for further discussion/clarification.


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## boredatwork (Sep 14, 2007)

I agree with most of your comments. I was purposely using sweeping generalizations. I didn't even intend for it to be that long. To get into specifics I would have ended up writing a book, haha. But I am always up for further discussion.

As for having separate mechanical and bio media I don't know how I feel about the skepticism about not cleaning bio media. I have an FX5 with the stack of prefilter foam and I fill all of my media baskets with poly fill. When I clean my filter I wash out the pre filter foam in dechlorinated water and usually replace the poly fill. So basically I am cleaning all of my filer media and I have never had a problem. I need to have a better understand of how the bacteria attach themselves to the media. For instance in the process of rinsing out the foam are the bacteria "falling off" of something? I don't know. I think to be safe, people separate bio and mechanical media for this reason, but I am not sure how necessary it is. Even still, I will agree that it is a safer approach.

As for the media application, I would still say that both "types" can and will do both - of course this is depends heavily on what type of media you are using. And when you say detritus what you mean by that? If you are specifically referring to large poo particles than in a normal filter I agree the bio media probably won't see it - but if detritus means any unwanted particle then I disagree. For instance if in your filter you use a coarse foam followed by a medium foam followed by your bio media, then by the time the water hits the bio the poo is probably filtered out. But if you are using matrix for you bio, that could filter out smaller particles that made it through the foam. I guess I could give 100 examples of different media combination that could illustrate 100 different scenarios which is kind of silly. The main point is that the media itself will end up doing some amount of both - the ratio will depend on the setup you have, but they will do some amount of both. And I think the mechanical acting as bio is more probable than the bio acting as mechanical. Especially in a "standard" filter setup. When I say standard filter setup I mean a filter where the media is course mechanical media followed by medium to fine mechanical media followed by bio media.

As for chemical filtration that is a good point. Not much more to say about that.

As for water flow - to have no flow in a tank is a bad thing (most likely). However, I am assuming some common sense is applied (which I acknowlegde is a grand assumption). And what I meant is to say that as long as there is not stagnant water, GPH is not really an indicator of filtration - as you already pointed out in the previous post. To me there is a very weak connection between GPH and filtration effectiveness.

As for mechanical filtration being complete removal of waste from the system, I would not disagree with your intent, but I don't know if that is a conventional understanding. I fully advocate and implore people to remove the waste rather than keep it sitting in the filter for months. But I view that as a separate step. To me, mechanical filtration is purely the transfer of waste from the tank to the filter media. I think its just semantics.

As for GPH having little effect on bio of mechanical filtration, again I am assuming some amount of common sense. But I think in terms of a definition of filtration GPH does not enter the picture - at least not in a deterministic way. I do not disagree with the rules of thumb that are out there (e.g. 10x turnover etc) - but their effectiveness is not in the rule itself. As was already pointed out there is a very weak connection between GPH and effective filtration. As for UGJ, well, we know where that ends up, hahaha. I also don't want to say that more increased flow is a bad thing. I think more flow is good in a tank for many reasons, but above a reasonable threshold I don't think it adds any additional benefit to filtration. I guess you could say "little effect" does not equal "no effect". My overarching thesis is that I think there is little connection between GPH and filtration. Again, by saying this does not mean I am saying flow is not important.

Lastly, and this one is not in order, you mentioned about needing mechanical filtration. I would clarify that to say I don't think you need to have mechanical filtration media. I will still maintain that mechanical filtration media is not necessary. Of course this assumes my definition of mechanical filtration and not yours. If we use your definition then it is absolutely necessary. The difference is the removal of waste from the system. Even if I am saying you could get away without mechanical filtration media, you would still need to vacuum the substrate and clean out the filter. And ultimately, if you have any kind of external filter it is going to perform some amount of mechanical filtration even if it is only stocked with bio media. In that sense its kind of a silly point. But my intent was to say that if you don't care about the clarity of your water, don't worry about using mechanical filter media.


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## MP Aqua (Jan 17, 2009)

Thanks for the discussion prov356 and boredatwork! This is good stuff. :thumb:


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## KaiserSousay (Nov 2, 2008)

> clarity of your water, don't worry about using mechanical filter media.


Which would also throw out the whole gph thing, larger volume of particulate rushing in to be filtered out. Purely an eye candy thing for me, not the fish.
Saw an interesting post about fry, and crystal clear water. What are the fry feeding on untill large enough for flake. Is it possible for us to filter out, UV, the food they feed on??
BAW and prov356, as always :thumb:


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## prov356 (Sep 20, 2006)

> And when you say detritus what you mean by that?


Any organic particles of poop or uneaten food, etc.

I know what you mean about writing so much you're writing a book. I tend to leave things out too. My 
practice with mechanical media when I say clean aggressively, means not just thoroughly, but often. 
So, you pretty much inhibit bacteria growth. I put my prefilter pads under sort of a pressure wash 
with a hose attached to the tap, so chlorinated water. I then let them to dry. I have another set that I 
put into the tray. I keep swapping them out this way, so I start out with a 0 bacteria count each time. 
My goal is not to prevent bacteria growth here, but remove organics completely and often. I rely on my 
biomedia to do the biofiltration, and in time of course every surface of the system becomes 
'biomedia'. It's just goes with a philosophy of mine to remove organics as often and as thoroughly 
as possible. Separating media makes it a whole lot easier to do that. But, you're right, too many 
examples to get into. Sounds like you're talking canisters and I'm talking drip trays, so we're not 
comparing apples to apples at all. I take a different approach with my canisters, but still try to open 
them often.



> To me, mechanical filtration is purely the transfer of waste from the tank to the filter media. I think its just semantics.


Maybe so, but if I had to formally define mechanical filtration, I'd say removal from the system, not 
water column. Otherwise, getting lodged under a rock would be considered mechanical filtration. 
So, it's just the way I like to think of it and refer to it here.

I better get to back to work.  Good discussion though.


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## boredatwork (Sep 14, 2007)

prov356 said:


> I put my prefilter pads under sort of a pressure wash
> with a hose attached to the tap, so chlorinated water. I then let them to dry. I have another set that I
> put into the tray. I keep swapping them out this way, so I start out with a 0 bacteria count each time.


Yea that important to know. I just scrub mine in dechlorinated water to get all the poop out. The assumption is that doing it this way does not ruin any significant amount of bacteria. Although, you have me thinking. I always struggle with green water and diatoms. I can always fix the green water pretty quickly, but I am too lazy to keep up on it all of the time. But I am sure a more thorough cleaning of the filter would be helpful.



prov356 said:


> Sounds like you're talking canisters and I'm talking drip trays, so we're not
> comparing apples to apples at all. I take a different approach with my canisters, but still try to open
> them often.


Yea, I am referring to a canister. I think that makes a difference as to what media you use . I cant see filling a wet/dry with all filter floss, haha.

I


prov356 said:


> better get to back to work.  Good discussion though.


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