Coil Denitrator

[richdragon32]

Anyone has made a coil denitrator? And if so, was it helpful in removing nitrate from the water?

[rsman]

I have made a few of them, I have one on my reef, though I dont think I would recomend them on a reef, they wont reduce nitrate down quite as low as LR/DSB IME, but in a FO or nano or .... there really good at keeping the nitrate < 5ppm sizing them for the job can be dificult but not impossible so be prepaired for initial mistakes there. feel free to go overboard it wont harm anything, but wont really reduce nitrates any further.

they can be work to get cycled, but once there cycled its really easy to do.

[WmTasker]

Originally posted by rsman
I dont think I would recomend them on a reef, they wont reduce nitrate down quite as low as LR/DSB IME, but in a FO or nano or .... there really good at keeping the nitrate < 5ppm

I have a 75 gallon reef and I was thinking about putting a Denitrator Coil on my reef. But you don't think that it will take the nitrates lower than 5 ppm? I keep it about that with the LR and refugium. I was wanting to take off the refugium and get the nitrates to zero.

Do you think it would be worth my while to make one, for what I am wanting to do? Or should I keep the refugium?
Billy

[rsman]

A coil denitrator with your refugium will get nitrates to 0, but IME they just dont lower nitrates below 3~5 ish ppm, using the coil will allow the refugium to work on the lowered ammount, allowing lower numbers with either increased bio load, or not enough nutrient export methods, or both

[rsman]

sorry last post should have said "will help to get " instead of "will get", though the odds are in favor of hitting real low numbers with both.

[WmTasker]

How low do you think I might be able to get it with just a coil and no refugium? The refugium takes up alot of room, and Im wanting to put a calcium reactor and coil on it. Do you know where there are any good plans for a coil?

Billy

[rsman]

as far as how low itll go, oversized does help, I have a nitra-max (rated for 100gal tank) on a 10, and a smaller one on another 10, there populated differently, and nitrates are below 5ppm its been my observation that the 3~5ppm is the lowest the coil will do alone, now the 10's are both FO and have either little or NO LR and have shallow CC beds and bio wheels IF there was still a second export method (dsb/plennum/lotsa LR/waterchanges ...) you should hit 0 w/o a refugium

as for sites with plans, I know there used to be, I dont recall where, its not exactly brain surgery there almost idiot proof to build. long coil, bunch of bio balls all sealed up, it doesnt often get easier than that

HTH

[richdragon32]

Billy, I found some DIY sites, but I gotta look for them again. . But I can tell you some of the materials:

1. From any hardware department store get a black drip irrigation tubing. It's black so algae won't grow on it and it's cheap! I bought a 100ft for $5.
2. Air sealed bottle to fit all the 100ft tubing in it.
3. Water pump
4. Valve to control water flow.
5. The actual directions to make it.

I'll see if I can find the site again or use the keywords "DIY Coil denitrator" in a search engine.

Best wishes,

Richard

[TiTAN]

OK it is easy enough to make the Coil Denitrator, but how is the flow into the cannister controlled if you are using a pump and the desired rate is about 60-90 drops depending on the nitrate level leaving canister.

Adjusting the speed of the water leaving the cannister is also the easy part, but if only 60-90 drops leaving the cannister how can you have a pump on one end pumping the water in??

Thanx

[WmTasker]

RichDragon

Most of the DIY sites I have found use Bioballs in the filter for the Bacteria to colonize on. Is that really needed? Does it matter what the diameter of the tubing is?

[WmTasker]

rsman

Do you think the combination of coil, over 100lbs of live rock, and the use of a nitrate sponge will get to 0ppm?

Sorry for asking so many question This is the only place on RC that I have found people that use the coil and will talk about it.

Thanks Billy

[richdragon32]

The bio balls are placed after the water has gone through the tubing so that more anaerobic bacteria can grow. I have found some sites where they wouldn't recommend it because the water coming out of the denitrator will be more toxic. But I figure if the tubing is long enough then I wouldn't need the bioballs. I believe the tubing diameter does matter, generally the smaller the better because there's more contact from the water to the tubing where first the aerobic bacteria can grow and use up the oxygen and through the tubing as oxygen become depleted, the anaerobic bacteria can grow. That's why if you're tubing is long enough, I don't see the necessity to put the bioballs. The most important thing is the water flow: too high makes it a nitrate producing filter and too low will cause it to produce toxic hydrogen sulfate and really stink up the water. Normally I would put the water out from the denitrator in a sump full of aeration so the hydrogen sulfate can (for lack of a better word) "go away".

[richdragon32]

Originally posted by TiTAN
OK it is easy enough to make the Coil Denitrator, but how is the flow into the cannister controlled if you are using a pump and the desired rate is about 60-90 drops depending on the nitrate level leaving canister.

Adjusting the speed of the water leaving the cannister is also the easy part, but if only 60-90 drops leaving the cannister how can you have a pump on one end pumping the water in??

Thanx

I found a cheap powerhead or a small pump from those tabletop water garden works, as long as you can figure out how to attach it to the small tubing. When you buy the drip irrigation tubing there's also valves to control the drips on the outgoing end. So the pump remains at full power at the incoming end, but at the end of the tubing is where you can control the drip using the valve.

It is totally worth it to make the coil denitrator yourself. I found one denitrator product to go as high as $90 and the supplies I bought was $15 + the labor working on it.

[richdragon32]

Billy

I did have a nitrate crisis a few weeks ago, but the combination of live rocks, higher algae, 3" of sand bed, and the coil has helped A LOT. I don't know what the nitrate level is now (haven't tested it), but I can see from my corals that they are extending out more, my xenias aren't closed up, no red slime... that I guess it's working. I haven't tried the nitrate sponge but I'm sure it'll help too.

[tag007]

On any of these denitrators, do you drip any de-nitrating formula. When I think back to the old denitrators, wasn't there a fluid you had to add? And wasn't there something that you could use to facilitate the growth of phosphate reducing bacteria, some other fluid? I thought these went "out of style" years ago...

[WmTasker]

tag007

I don't care how out of style they are. If they work its going on my reef I know that Coralife has a food called Ana for anaerobic baterial growth. http://www.esuweb.com/new_site/ccc_s...ents_4.php#ana

I don't know if this is what you were talking about, b ut I was thinking about using it.

[tag007]

Wasn't meaning to critisize, just find it funny how things that do work are dropped for "better" methods within this hobby. I was actually thinking of doing something like this on my nano, but you don't find too much first hand experience with them these days.

Thanks y'all for this discussion and info.

-Trent

[rsman]

ok lots to reply to,

as for the nitrate sponge skip it

as for the plumbing driping into a sump is the best aproach, otherwise a bypass on the output of a small powerhead will do the trick

as for 100lbs of LR and a coil should be good to hit near 0 numbers

as for feeding, you dont feed coil denitrators, the coil does the work

as for the slower flow, its most important during the cycling of the unit to have the low flow, after its cycled you can bump this up fairly significantly though its still slow, its faster than 45~75 drops / minute

the tubing should be small in diamiter if you want more output use more than one coil also smaller diameters allow faster flow to a point which helps.

use the bio balls and chaimber itll increase your total possible flow (after it cycles)

I think that covers it all

HTH
and ask away I myself like them, I use them more on Fo's and such but I still like em.

[bbragg]

My understanding in some of the literature and research on nitrate reduction in wastewater is that some form of carbon is required to bring the process to a high efficiency. For example, solutions containing glucose or methanol or acetic acid. I believe the AquaMedic reactor uses a solid medium as both the colonization area and food source that must be replced periodically.

I was thinking about building a coil denitrator and testing its effectiveness. Then adding a colonization medium and remeasuring, then finally adding a carbon source (acetic acid) and checking its efficiency again. Trying to gauge the effects. Difficult though as the things seem to take quite a while to cycle into a peak activity state.

Any experience with these "carbon source" types?

[tag007]

The ones I rememeber had someting like an osmosis bag, and I believe the formula was some sort of glucose. Filled the bag with the fluid and set it in the denitrator. A month later pulled it out dumped what was in there, and filled it up again. Got expensive from what I recall. And the bag got a nasty pink and green slime all over it. I have also seen some with a small drip pump. I think some companies are still making this stuff. Maybe you could experiment with different carbon sources.

Do any of you return to your skimmer? I also thought that the water had to be aerated, and if possible ran through carbon before returned to the main sump. I thought this also was linked to flow rate, where if it was too slow, it could possibly run toxins back into the system.

-Tag

[rsman]

generally if the coil is long enough then you dont have to feed it, but at the same time, if the water isnt moving thru the unit fast enough itll create hydrogen sulfate gas, if its moving too fast itll create nitrite.

output into the skimmer is a good idea output into a refugium is a better one.

[bbragg]

The coil, I believe, is where the aerobic bacteria colonize and remove the oxygen and use ammonia and nitrites in the water as food. Beyond the coil, on some other substrate or medium is where the anaerobes do their business of cracking the nitrates into N2 gas. I beleive they require a carbon source and a low pH for the best efficiency. In fact, I've seen a study concerning wastewater nitrate removal that suggests a pH between 6.5 and 7.0 is optimal. I was therefore considering feeding the thing from my Calcium reactor as the pH of the effluent is about 6.7 and I'm running a drip rate of about 14ml/min.

[rsman]

The coil, I believe, is where the aerobic bacteria colonize and remove the oxygen and use ammonia and nitrites in the water as food.

that it is
Beyond the coil, on some other substrate or medium is where the anaerobes do their business of cracking the nitrates into N2 gas.

yep
I beleive they require a carbon source and a low pH for the best efficiency. In fact, I've seen a study concerning wastewater nitrate removal that suggests a pH between 6.5 and 7.0 is optimal.

the output water from the coil will (if it did its job) have a ph of below 7, when it removes oxygen it gives back co2, which is how it uses its carbon, and in doing so lowers the ph.

there is plenty of a carbon source in almost any fish tank to provide the bacteria.

I was therefore considering feeding the thing from my Calcium reactor as the pH of the effluent is about 6.7 and I'm running a drip rate of about 14ml/min.

be very very carefull here, the coils job is to consume alot of the oxygen, if it consumes too much hydrogen sulfate gas is released, to do its job it requires water with oxygen to be fead into it. without oxygen to react with the bacteria create hydrogen sulfate gas.

also look at the real need for efficiency in a fish tank you dont really need the unit to be super efficient, and it really wont help lower the nitrates any further

[Uncle-Edgar]

I might be jumping into the middle of something with both feet w/o truly understanding it, BUT, if 100 feet of black hose is good, wouldn't 200 be better. I've been quietly lurking in the shadows hoping to find reliable info confirming that the denitrators really work. I hadn't thought about smaller tubing, only, the bigger stuff.

If 200 is good what about 3. With the smaller tubing you could get a bunch in a reasonably small enclosure.

[rsman]

Originally posted by Uncle-Edgar
I might be jumping into the middle of something with both feet w/o truly understanding it, BUT, if 100 feet of black hose is good, wouldn't 200 be better. I've been quietly lurking in the shadows hoping to find reliable info confirming that the denitrators really work. I hadn't thought about smaller tubing, only, the bigger stuff.

If 200 is good what about 3. With the smaller tubing you could get a bunch in a reasonably small enclosure.

first off they do work. thats not really something to debate. does it work for fish tanks, thats up for debate, IME they wont remove all nitrate, but they will do a good job with alot of nitrate and for me thats good enough, ill allow my LR/DSB/plennum to handle it, or in my FO and breeding tanks ill live with the small remaining nitrate.

there are several problems with coil denitrifiers one being that the bacteria doesnt like being in high flow areas, another being that you want the coil to only remove ammonia/nitrite and alot of oxygen, the larger diameter tubing requires a longer coil, the smaller diameter tubing requires a shorter coil.

if your coil is too long then you have to go so fast the bacteria wont remove nitrate, or you will go so slow it will basically poision your tank.

if its too short its not effective at removing oxygen and you end up with a very slow nitrite source

instead of 200' you could run 2 100's though or 3 66's or 4 50's

the stiff vinyl tubing sold for ice makers at home depots in a 400' roll for $20 is nice stuff to use, and 75' works nicely, you can run many coils into a larger bio chamber and have a nice flow thru, IME it still wont lower nitrates below about 5ppm.


when i built the one on my breeding setup it cycled with only a few fish but was expected to handle much more than a few, its done its job well, but even with a few fish it still couldnt do less than 5ppm nitrates.