# Denitrate Tower - "Safe Denitrification"



## kmuda

Iâ€™ve had a few questions about my Denitrate Tower, so I thought I would provide a thread with a few details.

The â€œDenitrate Towerâ€


----------



## Malawi_Junkie

Man, I don't know what to say but IMHO overkill. 
A+ for creativity but it's a little much don't ya think. I guess you really can't overfilter your water but is it worth all your effort, is this really cutting down on your maintanence or adding to it. All the equipment kinda takes away from the fish.
You have obviously worked very hard and thought this out so if it works and your happy then thats what counts.


----------



## KaiserSousay

daughter calls â€œKing Kongâ€™s Bongâ€


----------



## kmuda

Malawi_Junkie said:


> Man, I don't know what to say but IMHO overkill.
> A+ for creativity but it's a little much don't ya think. I guess you really can't overfilter your water but is it worth all your effort, is this really cutting down on your maintanence or adding to it. All the equipment kinda takes away from the fish.
> You have obviously worked very hard and thought this out so if it works and your happy then thats what counts.


The intent has never been to "cut down on maintenance". The intent was (is) to provide optimal water quality.... and your not going to beat zero nitrate. I also have very soft water with a KH of only 2dGH. A side effect of the denitrification is that my KH does not erode, resulting in fluctuating PH values. So I've killed two birds with one stone (so to speak). Very healthy and stable water.

For me, the water itself is as much a part of the hobby as the fish. Understanding the biological and chemical processes involved is a perpetual learning experience.

As for the "monstrosity", I started small. I've tried many configurations over the last three years. I could see results, just not "enough" of a result, so the filter got bigger, and bigger, and this is what I wound up with. It's is what worked.


----------



## prov356

Fantastic, fun stuff, good job. =D> You should submit this for inclusion in the forum library.



> One of three things occurred. The micron filter itself is made of cellulose, cellulose is an organic carbon source. Perhaps there is enough break down of the micron filter material that it is serving as an organic carbon source for the denitrifying bacteria. Another possibility, this one is at least a certainty, is that the micron filter is removing all detritus (even microscopic) which allows the pores of the media inside the filter to remain open, enhancing denitrification efficiency. The final possibility is that it is serving no (or limited) purposeâ€¦. that the filter was going to achieve zero nitrate creep and adding the Micron filter was only a coincidence. The only certainty is that the Micron filter limits maintenance requirements of the denitrate tower as absolutely no â€œgunkâ€


----------



## kmuda

The "denitrification media" I'm using is a combination of SeaChem deNitrate and Eheim Ehflilav (about a 5 to 1 ratio, deNitrate to Efhlilav). All of the media is about 3 years old. It was last cleaned about 4 months ago when I moved from one (less successful) design to the current simplified design. The primary function of the Ehfilav is to prevent the deNitrate media from compacting.

The media is the real expense in this thing. While deNitrate is comparatively inexpensive, I have at least 4 of the 1.6kg buckets of it in use, at $29 per bucket.

For cleaning, I dump the media in a large container (33 gallon Rubbermaid trashcan reserved for fish use), fill it with water, swishing it around by hand to get the easy to clean stuff from the surface of the media, rinse it well (think of rinsing sand before using as a substrate), then boil it in multiple pots on the stove.

As you mentioned, flow rate is critical. Right now I monitor the flow rate by eye. I know what the outflow stream is supposed to look like and adjust the flow regulator if I sense a difference. I would love to have a flow meter on it but have not been able to find one that works at 30gph.

I recently allowed the flow to slow to a trickle (was not on purpose, life got in the way). I would guess it was at a trickle for a couple of days. The results were denitrification rates decreased and nitrates increased. I did not detect ammonia or nitrites, although that would be the primary risk (incomplete denitrification). If allowed to run at such a slow flow for too long, hydrogen sulfide would become a concern (and is one of the reasons I included Ehfilav in the media mix, to prevent the filter from compacting, reducing flow, and establishing the equivalence of a 7' deep sand bed). My experience is that there is virtually no reduction in flow for 2 weeks, so if you change out the Micron cartridge every two weeks, it should not be an issue. But that is on my tank, which is very heavily filtered elsewhere (C-360, 2217, 2215, HOT 250, Penguin 350, several air driven sponge filters). If you are less filtered you may not make it two weeks. I do, however, consider the Micron filter essential to success. If nothing else, it allows the filter to go numerous months without maintenance. On my "to do" list is to add a 100 Micron filter in front of the 20 to see if this expands the life of the 20 (which it will). But I gain nothing if I have to replace the 100 Micron every two weeks. I just have to try it and see.

The current build uses clamp fastened rubber couplings (on each end) that are easy to remove. Remove them and dump the media out. These are a "hazard" if you put too much pressure on the filter as they can pop off, which has happened once in the last three years but not with this particular design (that was a fun cleanup). With the current design, I stress tested it for a couple of days at full flow and they stayed intact. Since I am running at a very much reduced flow, I consider the current risk minimal but I do check them each weekend to ensure the screws are tight and the couplings have not moved (using a permanent marker I traced a line on the PVC where the coupling should be. If I see white behind the line, the coupling has moved, thus far they have not moved). But this was the driving factor behind "King Kong's Bong", using the threaded plugs to eliminate this concern. I have not stress tested "King Kong's Bong" yet. It's been too cold to play with water outside.


----------



## bulldogg7

> The "denitrification media" I'm using is a combination of SeaChem deNitrate


so the seachem denitrate doesn't work?


----------



## kmuda

Since I am achieving zero nitrate creep, I would assume the deNitrate media is working. As I stated in prior posts, the primary purpose of the Eheim Ehfilav media is to prevent the deNitrate media from compacting.

EDIT:
I should also clearly clarify that I've been through several builds over the last three years (all using SeaChem deNitrate). Not all of them worked as well as the current one. The only thing I can testify to is... in my tank...

1. A 7' tall PVC pipe filled with a combination of SeaChem deNitrate and Eheim Ehfilav
2. A flow rate of 30gph
3. Prefiltered by a 20 micron filter

Has resulted in zero nitrate creep for the last several months. Actually, this is not entirely accurate as when I allowed the flow to reduce I started getting nitrates again. This corrected itself a few days after I corrected the flow.


----------



## kmuda

I thought I would show you guys evidence of what this filter will do. Below is a pic of nitrate tests from last week. I perform daily nitrate tests and have a photographic record of them going back a couple of years.

The only true "zero nitrate" readings are on Friday and Saturday. The preceeding 5 days the filter was recovering from a drop in flow rate.










I did not perform a water change this weekend, so we'll see what happens next week.

Back several years ago, I declared war on nitrates. I can honestly say it can be done. Zero Nitrate creep can be achieved. The remaining question is how long and how finicky. Thus far, it's been over a month and the filter has remained effective and stable, as long as I do not let the flow rate drop.

I have another experiment ongoing at the moment concerning nitrates but I need to start an additional thread to detail those results, but let me throw this out there.

Here are nitrates on each of my 4 "primary" tanks as of 10/24/09.









Here are nitrates on each of my 4 "primary" tanks as of this weekend (12/19/09)









Each pic is an accurate representation of a weeks worth of nitrate creep on that particular tank as nitrates are reset to zero each week via 100% water changes. In the October 24th pic, this included the Oscar tank. While I continue the 100% water changes in the other tanks, water changes have been drastically reduced in the Oscar tank with no water change being performed this week. None of the reduction is a result of decreased feeding or increased water changes.


----------



## fox

For the last 5 or so years I have been controlling nitrAtes with plants. I have tried different combinations and nitrAte levels and find having a nitrAte level of 10ppm or so gives the clearest water collumn. If I let it go lower I start to get some weird algae that goes away as soon as the nitrAtes rise to 10ppm or so again.

I have gotten 0ppm nitrates with dozens of very large fancy goldies in a large tank w/ out doing a WC for 1 month. Guilt set in and I started a WC schedule every 2 weeks anyways and gave the excess ***** tail and duck weed to the fish as treats.

I have since scaled down the plant growth to slower growing varieties and no more floaters that require the most maintenance. This keeps my weekly nitrAte levels at 20ppm with a very heavy fish stock and 25% weekly WC's. I have gone 2 weeks with this setup and still maintain 20ppm nitrAtes, I have yet to go 1 month as I generally do not mind doing the maintenance on my tanks.


----------



## kmuda

I would like to emphasis that my attempts at nitrate reduction are not an effort to reduce maintenance. They are an effort to provide the best water quality as possible.

In general, I deal with large fish such as Oscars and this has been where my focus has been. When it comes to large cichlids, I've experimented using plant filters and came to the conclusion I would need a heavily planted tank about twice the size of the main tank to make much of an impact on nitrate reduction. In fact, if you review the above photos, the "Kissing Fish Tank" is a planted tank, heavily planted with Wisteria (Hygrophila difformis), a monsterously fast growing plant, as well as crypts and various swords. The plants effects on nitrate accumulation have been virtual nill. This tank happens to be my worst nitrate accumulator. I've also tried other super fast growing weeds such as water lettuce and anacharis.

For large fish at least, I don't think you will achieve significant nitrate reduction using plants. I am aware of one individual who managed to get nitrates to zero on his Oscar tank using terrestrial plants (which are better consumers of nitrate than are aquatic plants), but he turned one room of his house into a "filter room" using a waterbed as a sump. The room was packed with lighting and tomato plants growing hydroponically. Water from the tank was cycled through these plants. The entire setup was way to extreme to be feasible. I only mention it as an indication on how difficult it is to achieve significant nitrate reduction using plants (at least when dealing with large fish).


----------



## fox

I am getting very good results with my 2 small 12" f.rostratus, 2 smaller 9" venustus along with the other 2 dozen+ smaller cichlids with the smallest sizing a bit larger than 6" and a 40G sump/ fuge. I guess those Large Oscars are producing more trAtes than your planted solution could handle. Refugiums work, and very good at that, if you put the right effort into setting one up. I have found it takes about three months to get one working.

We raised Orandas and PearlScales for sale here to our local fish suppliers so I am pretty aware of good water conditions and its importance. Orandas get large, ours were in the 10 - 12" range and are very delicate, getting sick if you just look at them crooked. We would keep 30 or so in a tank and water conditions were very important. We found plants, duckweed and hornwort, to be great trAte scrubbers. Plants look pleasing also in the LivingRoom if you set the fuge up properly for show. There are a thousand roads that lead to Rome, and they all will get you there.

Good luck with your bong :thumb:


----------



## BenHugs

I'm all about tinkering with my tank I'm not sure I want a 7' tower in my living room though. I have a highly stocked african cichlid tank with planted fuge a philodendron growing out the back and a DIY protein skimmer that is actually working for me. I often toyed with the idea of putting a de-nitrifier into my system but the hydrogen sulfide part always scares me off.

Does the hydrogen sulphide stay in the water column or can it be "bubbled out"? Is it dangerous to the humans living in the room?


----------



## kmuda

I want to emphasis.... the 7' Denitrate Tower I am using is not an an anaerobic filter. It is what I term "safe denitrification". There is little risk of hydrogen sulfide or incomplete denitrification, which is a larger concern.

That said.....

Denitrification is dependent upon the amount of organic carbon in the tank. In anaerobic conditions, if there is not enough organic carbon then you wind up with incomplete denitrification, where nitrates are converted back into nitrite or ammonia. If there is too much organic carbon, you wind up with hydrogen sulfide production. In order for there to be "too much" organic carbon, you would have to be performing supplemental dosing with an external carbon source (sugar, alcohol, etc...) or you would have to make the mistake of allowing uneaten food or intact poo into the filter. Aside from that, the risk of "too much" organic carbon is pretty slim while "not enough" is almost a certainty.

Which is where the concept for the 7' tower comes into play. It is not anaerobic so the risks normally associated with denitrification filters do not apply. If there is not enough organic carbon to support denitrification, I just get reduced rates of denitrification, not incomplete denitrification. The micron filter eliminates the possibility of any organics (aside from dissolved organics smaller than 20 microns) from entering the filter and I don't dose with an external carbon source. So there is no risk of hydrogen sulfide production, and, as stated, the filter is not anaerobic, so hydrogen sulfide cannot occur. To the bacteria that produce hydrogen sulfide, the slightest hint of oxygen is toxic.


----------



## Pali

Very nice filter :thumb:

I might missed it, but is there a reason the filter is standing vertical or could it; Let's say be made into a U shape, and mounted horisontal under the tank for a "prettyer" look :wink:


----------



## newfisher

BenHugs said:


> Does the hydrogen sulphide stay in the water column or can it be "bubbled out"? Is it dangerous to the humans living in the room?


Denitrators typically produce very low concentrations of H2S. Some of it may dissociate in water to form sulphuric acid, slightly lowering water pH. However, if a denitrator output is allowed to drip through air space before re-entering water, most of the H2S will become airborne. It is characterized by rotten egg smell (swamp gas odour), noticeable at concentrations of about 0.005ppm. I surmise that typical denitrator production would be well below 1 ppm, and notwithstanding pH changes, would present an odour nuisance at worse to humans.

On the other hand, H2S is extremely well known and respected in the oil and gas industry, where I've dealt with concentrations above 8% (80,000ppm) back in my oil and gas exploration days. It is heavier than air, flammable, and very toxic in higher concentrations. H2S causes eyes to burn within minutes at concentrations above about 50ppm and eyes are damaged above 100ppm, it will deaden the sense of smell above about 100ppm (often causing potential victims to be lulled into thinking the gas has gone), and cause immediate collapse at concentrations above 500 to 1000 ppm. Many oil industry workers have died trying to perform CPR on co-workers who have collapsed ... where there's often sufficient H2S remaining in the victim's lungs to cause his rescuer to collapse also on their first breath. Industrial personal and electronic sensors are typically set to alarm at 5 to 10ppm, above which emergency procedures are put in place and Scott Air Pack or central respirator use typically begins.


----------



## kmuda

Sorry for the delayed response, but please allow me to answer a couple of questions.

First, about attempting a "horizontal U-Tube" configuration. I've tried. It was not as effective. The primary problem is it is very difficult to get the tubes 100% full of media. Over time, the media settles and when the tube is placed horizontal this results in the media settling in the bottom leaving an open area at the top. Water will follow the path of least resistance, so the water ends up flowing on top of the media, resulting in much less effectiveness. I consider a filter where water is fed from the bottom and exits from the top essential for this type of filter (think Eheim Classic). Another option would be a very fat, shorter filter.

Secondly, please notice use of the term Ã¢â‚¬Å"safe denitrificationÃ¢â‚¬Â


----------



## BenHugs

Well thanks for all the info Kmuda and Newfisher.
Kmuda I just couldn't possibly put such a large pipe in my living room but still being inspired I went a built the classic coil denitrator. It may not be as "safe" as the one you built but it fits into my stand so nobody can see it.
I couldn't beleive how easy it is to build one of these things. I hope it all works out :thumb:


----------



## kmuda

Be sure to monitor the outflow of your coil denitrator for ammonia and/or nitrite. Coil denitrators are notorious for incomplete denitrification. You have to get the flow just right, constantly monitoring it.


----------



## BenHugs

Ya kmuda I have found similar info. To protect my system from what you mentioned it will have it's outflow going into my wet/dry filter which would just re-convert back into nitrates. My coil denitrator will be getting at most about 3gph so if anything maybe on the slow side?? Off the top of my head the coil section will have over 60' of tubing and the tower filled with bioballs is about 30" tall.


----------



## kmuda

It's a good ideal to have the outflow of your filter run through a standard aerobic filter. This will take care of both incomplete denitrification and/or hydrogen sulfide (entering the tank) concerns. I do, however, still recommend regular testing. It's the only way to know if the filter is working properly. If you detect nitrite or ammonia, the flow rate should probably be decreased. If you are still detecting nitrates (in the absence of nitrite), the flow rate should probably be decreased. If you smell rotten egg smell, the flow rate should be increased.

Also, if you are running carbon anywhere in the system, it should be removed as it removes the same stuff the denitrifying bacteria need to convert nitrate. If carbon is removing dissolved organics (which is what carbon does, on top of other things), this will increase the likelyhood of incomplete denitrification.

But it sounds like you've done the appropriate research, as would be logical for anyone constructing their own denitrator  so you are likely aware of this. Please keep us informed as to the success (or lack of).


----------



## jfly

your daughter calls it "king kong's bong!?!?!?" hmm and how old is she.. i'd kill myself if my kid said that, then myself for my parenting faults


----------



## BenHugs

Thanks kmuda I was unaware of the carbon part but I don't run it in my system anyways. I was thinking of using up some carbon that I do have on the outflow of this denitrifier just incase I did get the rotten egg smell.


----------



## mightyevil

jfly said:


> your daughter calls it "king kong's bong!?!?!?" hmm and how old is she.. i'd kill myself if my kid said that, then myself for my parenting faults


I doubt kmuda tought his daughter the word bong and what it does...


----------



## kmuda

My daughter is 23. If "bong" is the worst word she uses, I would consider that successful parenting. 



BenHugs said:


> Thanks kmuda I was unaware of the carbon part but I don't run it in my system anyways. I was thinking of using up some carbon that I do have on the outflow of this denitrifier just incase I did get the rotten egg smell.


You don't have to worry about it. As long as the outflow is running through aerobic filter media, if hydrogen sulfide is occuring bacteria will become established that will convert the hydrogen sulfide to sulfate, which will eliminate the odor.


----------



## BenHugs

Kmuda :thumb:


----------



## ncutler

BenHugs just directed me to this thread since I'm looking at ways to decrease my Nitrates.

I'm definately will be trying to build a Coil Denitrator, but I had the idea today as to whether anyone has ever tried to use an air pump to create the flow for the denitrator.

In my mind, if I attach a vertical section on the output side of it, the venturi effect created by the air (much like a sponge filter) might move enough water through the denitrator to create 80 drops/minute as I have researched to be a good amount.

Perhaps this would make it harder to adjust, though I can't see why I couldn't add a ball valve before the air to adjust the speed.

Just curious as to your thoughts about it.


----------



## tranced

jfly said:


> your daughter calls it "king kong's bong!?!?!?" hmm and how old is she.. i'd kill myself if my kid said that, then myself for my parenting faults


you would kill yourself, and then yourself?

i think you have more to worry about than your parenting skills

that aside, awesome project here, was a good read interesting stuff keep it up


----------



## kmuda

Sorry to dig up an old thread, but I wanted to update it with a final piece of data. The filter has yet to be broken down and cleaned, but it now needs it. It is no longer able to maintain zero nitrates. Nitrates are now increasing about 5ppm per week, which is still a significant reduction over what would occur if the filter were not in place.

So now I know.... I get about 6 months before it needs cleaned. Now it's time to replace it with King Kong's bong (filled with new media). The current filter will be broken down, the media cleaned, and in about 3 months, added back to the system, to run in conjunction with King Kong's Bong. So every 3 months, one of the two will be broken down and cleaned. In theory, I should be able to maintain zero nitrates almost indefinately. The next question to answer, is how long can I continue to recyle the media?


----------



## BenHugs

Kmuda have you looked into the np biopellets?


----------



## kmuda

I guess not, since I'm not familiar with the name. Do you have a link?

EDIT......
Disregard.... googled it.

I am not familiar with the specific product, I am familiar with the technology (been waiting on products to start appearing on the market). If they are using PCLs (polycaprolactone) I wonder how they got around the Tetra Patent?

http://www.freepatentsonline.com/7244358.html

I'll research a bit more and post back.


----------



## kmuda

There is a suprisingly lack of information on the product. I would like to know specifically what biodegradable polymer they are using. As previously mentioned, Tetra/Marineland/United Pet Group has the most effective of these materials (polycaprolactone) locked up in patent. Perhaps that is why there an absence of information.... don't want to be found in violation of a patent.

Another concern is that it is marketed specifically for salt water tanks as a alternative to Vodka dosing. My experience with Vodka dosing in freshwater is that it's not a good thing. You wind up with heavy bacterial slime on everything and substantially increase the colonies of heterotrophic bacteria in the tank, many species of which are pathogenic (causing everything from kidney infections, to bloat, to pop-eye, to flesh ulcerations). They also specifically mention having the outflow from the NP-BioPellet reactor releasing into the intake of a protein skimmer to minimize the amount of bacteria being released into the tank. The "released bacteria" is also a food source for corals and other saltwater critters that do not exist in a freshwater tank. For me, another warning sign against use of this product in freshwater (or by anyone other than an advanced aquarist).

The Tetra patent (see previous post for a link to the patent) has resulted in the release of this product (Instant Ocean Natural Nitrate Reducer)
http://www.fosterandsmithaquatics.com/p ... atid=21331

Which I have been using for a few months as a test in my guppy tank and one of my Angelfish tanks. My issue is that I just don't allow myself not to perform water changes to determine how effective the product is. So I use the product and continue my water changes. But I have seen some results and my results don't match the patent. I'm getting better results in the sand tank than I am in the gravel tank. Another problem with it's use in a gravel tank is that if you gravel vac (which you should), you vac a good percentage of the product out of the tank. I don't mess with my sand, other than to vac up whatever is visible on the very top of it.

In the guppy tank (actually, it's a livebearer tank, containing guppies, platies, and swordtails -as well as cories) I am now going two weeks between water changes. Nitrates in this tank, before I did anything to control nitrates, (believe it or not) were the worst of any of my tanks. I added an Eheim 2213 filled with SeaChem Matrix and started using this product. Now... I don't quite hit 20ppm within two weeks. I was hitting well over 20ppm within a week (very heavily stocked). Supposedly, according to the product (with it's weekly use), nitrates should stablize between 10ppm and 20ppm, without water changes. I just can't allow myself NOT to perform a water change for a month to see what happens. I need to unpucker the sphincter muscles, on the subject.... I guess. 

In the Angelfish tank (gravel), nitrates where not exceeding 10ppm in a week and still are not, but I continue with weekly large water changes on this tank. There certainly is not any evidence of a reduction of nitrate creep in this tank, at least not with the weekly large water changes in play.


----------



## kmuda

As a followup... I sent an email to Instant Ocean asking them about "Natural Nitrate Reducer" use in Freshwater. Their response.... it does not work in Freshwater. So if Natural Nitrate Reducer is not going to work in Freshwater, then NP BioPellets most certainly are not.

Instant Ocean's recommendation? Being from the same parent company as Tetra, they recommended Tetra Easy Balance. Yeah.... right. That **** is not coming with a lightyear of one of my tanks.

Anybody wanna buy a couple of bottles of "Natural Nitrate Reducer"... cheap. :lol:


----------



## BenHugs

Thanks kmuda great research :thumb:


----------



## kmuda

I have not given up yet..... because Tetra sells (what I assume is) an identical product to "Natural Nitrate Reducer" in Europe (Tetra Nitrate Minus... which has Angelfish on the bottle cover). Historically, Instant Ocean is the saltwater arm, "Tetra" is the freshwater arm, of the same company. I've reread the patent upteen times. There is no mention to saltwater (no mention to freshwater either). It does identify the positive effects on plant root structures, which I would take to indicate freshwater use.

Now... all of that said, I would assume NP-Biopellets are using polyhydroxybutyrates (PHB), not polycaprolactone (PCL), as PHB's are not covered by the Tetra patent. NP-BioPellets are also using a very much larger pellet (Natural Nitrate Reducer uses a powder suspended in a liquid).

If nothing else, NP-BioPellets could be used with the addition of a functional skimmer. In freshwater, this is difficult, unless you have $1,000 to cover a Clarity. I am not sure why NNR is "saltwater only" but intend to find out.


----------



## BenHugs

I actually have a functioning skimmer on my malawi tank. It works on gravity with airstones to suppliment it. I do run some marine salts (1 scoop per 5g) and have a ph of around 8ish. I also keep my temp a little lower at 77 as that helps with skimming. I would show you pics but I need to build a better version. I'm going to see if I can find the link of a similar design. My skimmer requires a sump to work.


----------



## BenHugs

Here's the link. My protein skimmer runs the whole overflow system through it and I adjust the height of the collection cup instead of having the gate valve. I don't have the pump on my it's fed by gravity alone.
http://www.reefworkshop.com/DIY_gravityassistpump.htm


----------



## kmuda

I thought I would drop a quick update. I finally broke down the old filter and replaced it with the "Big Ugly Green Thing" (what my wife calls it), aka "King Kong's Bong" (my daughter's name for it).

This will be the third "recyling" of the media in this filter. I'm anxious to see if it continues to work after this latest cleaning.

Anyway, as my wife was complaining as I set it up, I claimed "Hey, at least I painted it green to match to house colors". :lol:

Here is a full on shot of the filter. It's in a small bucket just to ensure there is no leakage. Access to the media is a threaded drain plug on the bottom.









And here it is in it's normal position (to the right of the photo), partially obscured by the cabinet I store my extra media in.









The filter had pretty much ceased holding nitrates to zero, with the decline occurring after 6 months of use. We'll see if it gets things back into shape. I expect it to take a month to "recycle".

Cleaning involved emptying the media into a large container, flushing it clean with tap water, stirring the media by hand to force the individual media pebbles to rub against each other, then boiling for about 30 minutes.


----------



## John27

That thing is ugly but it looks like a great addition to a fish room or in my case, I have a closet right next to my 75, I wonder if I could fashion something like that, shoved in the closet and invisible?

Also, I love the idea, not trying to skimp out on maintenance but just trying to provide the best environment for your fish. I talk alot about survival vs. thrival. If you got rid of half or more of your filtration, did a 20% water change twice a month (and occasional big water change when nitrates got super high) your fish would not die. However, they wouldn't have the quality of life nor display the coloration, personality or natural behavior that they most likely do in your tank. I just love that instead of using your denitrate tower as a way to not do any water changes, your doing it as a way to provide pristine water. Good for you! Heck and maybe your like me and you love to perform aquarium maintenance! I love it when I change the water, now, when family members want to use the bathroom and there is a silicone hose running into the bathroom sink THEY don't like it so much, but you know, I'm still having fun :lol:

-John


----------



## moto_master

kmuda said:


> The filter had pretty much ceased holding nitrates to zero, with the decline occurring after 6 months of use. We'll see if it gets things back into shape. I expect it to take a month to "recycle".


Hey Kmuda, I've come across your thread a couple of times, and I'm wondering if you could give us an update? I'm thinking about building a denitrator...


----------



## Mxx

Hi Kmuda, great thread. And very helpful in terms of providing actual information based upon personal experience with denitrification. I joined this forum just to contribute to this discussion, so I hope that some people are still listening to this thread!

I'm trying to figure out the optimal approach for my own intended denitrification, so if you could further comment on a few things then that would be much appreciated.

I'm reading a lot of mixed opinions on Seachem denitrifying media, and I'm a bit surprised by certain aspects of how you've approached your denitrification filter. Let me explain, in reading Ecology of the Planted Tank by Walstad, she talks about how biofilms are actually a complex bacterial ecosystem composed of many layers of different bacterial species. (And biofilms are good of course, for they are the bio-filtration itself. In any case, in an established bio-film, the upper layers can actually consume all the oxygen, which supposedly enables the lowest layers to be composed of denitrifying anaerobic bacteria.

I'm not quite sure why your filter then ceases to function effectively after a few months, for denitrifying filters are just supposed to get more effective over time? Is it that it simply becomes physically clogged to where all flow through the filter is significantly reduced?

I was quite surprised that you actually remove the media and boil it, as anaerobic bacteria supposedly take weeks or even months to fully establish themselves. Have you ever tried simply cleaning the media manually by rinsing it under a strong jet of water instead, to get rid of any 'silt' on the surface? Perhaps if you ran the water through a prefilter stuffed with foam or floss which you instead rinsed regularly then you wouldn't in any case be getting any 'silt' into the filter?

I'm just surprised that your filter seems so finicky in terms of its effectiveness for denitrification. Have you considered using Seachem Matrix or Pond Matrix instead? As those have larger 'nugget' sizes, I thought they might be less sensitive to variations in flow then the smaller De*nitrate which you are using. And with only 30 gph going through a filter of this length, I even wonder if you're getting into the realms of a traditional anaerobic denitration coil filter, and whether all the oxygen is consumed before the water passes all the way through, which is perhaps something to do with why you're getting varied results?

Another factor is that denitrifying bacteria also require a compound which can act as an electron donor in order for it to chemically reduce nitrate molecules. And for that reason, aquarists add sugar, a few milliliters of vodka, or Tetra Nitrate Minus to their tanks. Municipal wastewater plants use a product called MicroCÃ¢â€žÂ¢ which is apparently similar. So perhaps when you're not getting denitrification, it has something to do with a lack of an available carbon source in the water.

Personally I'm considering minimizing water changes in my planted tank to enable DOC's (dissolved organic carbon), to build up a bit in my planted tank in case that helps achieve denitrification. I haven't yet found a conclusive answer through research as to whether this would though. I will also need to stop using activated carbon in my canister filter as well if that is the case. Anyone? Are DOC's a carbon source which would successfully fuel denitrification?

I suppose I'd personally plan to use Seachem Matrix or Pond Matrix, or possibly sintered glass in my filter, so that I wouldn't need to worry too much about maintaining flow rates as carefully as you're having to. And as the internal area is considerably greater, would they perhaps have greater denitrification capabilities than an equal volume of De*nitrate? Please advise if you can, thanks!


----------



## Agridion

Mxx said:


> Another factor is that denitrifying bacteria also require a compound which can act as an electron donor in order for it to chemically reduce nitrate molecules. And for that reason, aquarists add sugar, a few milliliters of vodka, or Tetra Nitrate Minus to their tanks. Municipal wastewater plants use a product called MicroCÃ¢â€žÂ¢ which is apparently similar. So perhaps when you're not getting denitrification, it has something to do with a lack of an available carbon source in the water.
> 
> Personally I'm considering minimizing water changes in my planted tank to enable DOC's (dissolved organic carbon), to build up a bit in my planted tank in case that helps achieve denitrification. I haven't yet found a conclusive answer through research as to whether this would though. I will also need to stop using activated carbon in my canister filter as well if that is the case. Anyone? Are DOC's a carbon source which would successfully fuel denitrification?


Are there any other ways to add DOC's to your sytem besides the 3 methods you mentioned above? Wouldn't having a planted tank supply enough DOC's to our system especially if you had a CO2 system so your plants could absorb the CO2 and not the organic carbon in the water?


----------



## Mxx

Agridion said:


> Mxx said:
> 
> 
> 
> Another factor is that denitrifying bacteria also require a compound which can act as an electron donor in order for it to chemically reduce nitrate molecules. And for that reason, aquarists add sugar, a few milliliters of vodka, or Tetra Nitrate Minus to their tanks. Municipal wastewater plants use a product called MicroCÃ¢â€žÂ¢ which is apparently similar. So perhaps when you're not getting denitrification, it has something to do with a lack of an available carbon source in the water.
> 
> Personally I'm considering minimizing water changes in my planted tank to enable DOC's (dissolved organic carbon), to build up a bit in my planted tank in case that helps achieve denitrification. I haven't yet found a conclusive answer through research as to whether this would though. I will also need to stop using activated carbon in my canister filter as well if that is the case. Anyone? Are DOC's a carbon source which would successfully fuel denitrification?
> 
> 
> 
> Are there any other ways to add DOC's to your sytem besides the 3 methods you mentioned above? Wouldn't having a planted tank supply enough DOC's to our system especially if you had a CO2 system so your plants could absorb the CO2 and not the organic carbon in the water?
Click to expand...

I'm guessing there must be various other ways to add organic carbon, but I'm not sure in what forms works as is necessary. I guess that I end up with a few questions I'm wondering about here; 
A: Does DOC act as a carbon source for denitrification?
B: What does this do to the DOC molecules then? Destroys them somehow?
C: To enable anaerobic denitrification, should I not use activated carbon in my filter as that removes the DOC's I may need for denitrification?
D: Does the use of a powerful UV sterilizer oxidize the DOC's and thus render them incapable of being used to enable denitrification?
E: What is the best size media to use in a canister filter to achieve the most effective denitrification, the smaller Seachem De*nitrate or the progressively larger Matrix or Pond Matrix?


----------

