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blastermqn

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I should first offer a disclaimer that I've never used a nitrate coil, and am not not trying to come up with a gizmo to relieve myself from proper tank husbandry. Still, I've found the concept of a biological de-nitrate device very facinating, and any practical device that aids in nitrate reduction to hardly be a bad thing in a marine tank. In my opinion nitrates are the single biggest problem in marine tanks and the biggest irritant for corals and even fish. Even with DSB's, expensive skimmers and mangrove plants I've often run into pesky nitrate issues and simply not willing to get rid of fish to solve the problem.

Looking at the typical design for a nitrate coil leaves me shrugging my shoulders because even though the concept is simple, they sure seem overly complicated.Basically you have a long length of black tubing with a low water flow dumping into a large reaction chanber containing bio balls or other media. The long length of hose acts as a bed for ammonia/nitrite reducing bacteria to colonize, and hence deplete the flowing water of oxygen. The low O2 water dumps into the large reaction chamber where nitrate reducing bacteria can thrive and (theoretically) chew up large amounts of nitrate. Easy enough.

Anybody who's had freshwater aquariums has at some point likely left a bucket of dirty gravel outside in the sun for a few weeks. Boy, it sure doesn't take long for anerobic bacteria to colonize the bottom layer of that crud judging by the smell that emits when you dump the bucket a few weeks later :) Also consider that DSB's are hardly as high tech as a nitrate coil, and basically just a static layer of fine gravel or sand. So, I'm thinking if a thick substrate of gravel or sand can host nitrate recucing bacteria, why the heck do we need that coil gizmo?

Here's my solution: Take a piece of 3"-4" PVC that's cut to a length 4-5" above your water line. This pipe is mounted in a common PVC flange/stand and sits behind your tank, or sump I guess. Bottom of the flange has a hole cut which is threaded and sealed with some thin tubing. You fill the main tube with substrate such as cheap crushed coral, or even used AC at the bottom. Sand seems like it would compact too much and inhibit water flow, but you get the idea.

Essentially all you do is pump water slowly into the top open end of the cylinder and as the water climbs and equalizes it will push a trickle out the bottom tube and back into your tank while having to flow through a few feet of gravel. The top of the subtrate will have no problems hosting the ammonia/nitrite reducers and the bottom part of the substrate should have no problem handling the nitrate end of the equation. A whole lot simplier than a coil if you ask me, and if you seed the top with some tank substrate will cycle much faster.

Thoughts? Opinions?
 

vegita

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I am interested in this myself. I think it should work if you have enough sand bed depth yet have water still pass through without oxygen. It's tricky. I wonder how effective those denitrating coils are.
 

Fatal Morgana

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Theretically, it should work, but from engineering point of view, there are many reasons why the commerical version use tubing and bioballs. One of the most obvious issue is the trapping of detritus with the use of fine substrate such as crushed coral. Another issue is the change in back pressure as the sand/crushed coral is packed differently, or during the usage. These make it a lot more difficult to use, and anyone with sufficient experience with the denitrator can tell you that it is not one of the simplest device in the hobby, and you don't want to make it any more difficult than what it already is.

For most purposes, denitrator is not really a good gadget consider the cost and benefit. Unless water chage is very expensive (say, if you live in the middle of Sahara desert), it is far easier to put the energy/money in a better water filter, better skimmer, and better nutrient export as well as limited feeding.
 

blastermqn

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Well, yes and no.

The biggest drawback I could see with this gadget is that it won't turn over enough water to benefit a large tank. On a smaller tank though like my 30 I could easily turn over enough water to make it a benefit, if perhaps I could get at least a 50% volumetric reduction in nitrate. By using less dense substrate at the bottom and more dense substrate at the top I could hopefully keep a fairly clean device that won't clog.

I agree with your comments about water changes, but in necessity and not in spirit. Unlike many marine aquarists, I've been moving to smaller and smaller tanks vs larger ones because I've moved 3 times in the past 5 years, and have learned that any significant water change that can't be accomplished with a single 5gal bucket and two trips tends to make me procrastinate. I'm also not thrilled about keeping half a foot of sand in a small tank.

Another thing I've noticed about small tanks is nitrate levels tend to want to climb to a certain point quickly after a water change, and then taper off after that. Even a huge water change results in low -10ppm nitrate levels for just a few days, and it rapidly climbs into it's so called saturation threshold until the next water change. I've found that most corals and sensitive inverts seem to tolerate nitrate levels to 10-15ppm with no reall issues, but moving to 25-30ppm is far more detrimental. While I only have sporadic problems with nitrate now, having a dedicated mechanism for nitrate export that works with the tanks biology vs simple chemical dilution is something at least I feel is worth exploring.
 
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Anonymous

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The entire idea of using anaerobic bacteria to consume nitrates vrs plant life to me is futile. No sense in risking pumping ammonia back into the system when the anaerobic bacteria is swamped or dies off.
 

blastermqn

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True, very true.

However, I've had half a dozen mangroves growing in refugiums on tanks with annoying nitrate problems, and have yet to be convinced they make much of a difference either.
 

Fatal Morgana

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mangroves are as mush of a hip as "plant life" (sorry, bob :D) if you look into the scientific facts. Think about how much nitrogen fertilizer it takes to grow a few pounds of tomatoes hydroponically. Most of the mass in a woody plant is not water like tomatoes, but if you convert all the mass to nitrogen, you will realize that you need to keep a huge mangrove in that little refugium to really make a significant dent on the nitrate.
 
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Anonymous

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All I know is my nitrates are 0.0 using less tank volumn than a dsb. Think I'll leave well enough alone.
 

ChrisRD

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beaslbob":er2kugo5 said:
All I know is my nitrates are 0.0 using less tank volumn than a dsb. Think I'll leave well enough alone.

Of the reef tanks I've setup and run for myself and for friends ALL have had undetectable levels of ammonia, nitrite and nitrate. In most cases the only filtration was live rock and a skimmer (some also had live sand). No "plant life" or DSB required...

FWIW, I have, in the last few years, experimented a bit with planted fuges, DSBs and going skimmerless - out of curiosity. Seems to me the old tried-n-true methods still work so I guess I'll leave well enough alone too.;)
 
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Anonymous

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ChrisRD":1emew75h said:
beaslbob":1emew75h said:
All I know is my nitrates are 0.0 using less tank volumn than a dsb. Think I'll leave well enough alone.

Of the reef tanks I've setup and run for myself and for friends ALL have had undetectable levels of ammonia, nitrite and nitrate. In most cases the only filtration was live rock and a skimmer (some also had live sand). No "plant life" or DSB required...

FWIW, I have, in the last few years, experimented a bit with planted fuges, DSBs and going skimmerless - out of curiosity. Seems to me the old tried-n-true methods still work so I guess I'll leave well enough alone too.;)

I have no doubt that is exactly your experiences. And as long as someone starting this hobby has lotsa plant life (algae) on and in the live rock then there is no suprise. But to me to say the only filtration is rock and skimmer is incorrect. With respect I think your rock was live with algae at least in the pores and very likely covered with corraline algae. In other words plant life.

And with a low bioload it is not suprising that was more than enough to maintain the system. I just prefer to support a higher bioload, with less space, and vastly reduced maintenance. By simply insuring thriving plant life regardless of the condition of the rock, sand or whatever else is in the tank.
 

ChrisRD

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Sorry Bob, I won't get drawn into this debate again as it's already been beaten to death elsewhere... ...if you had some experience with some of these other setups you'd probably understand what people are trying to tell you...

Needless to say there was no "plant life" on the live rock - the primary means of filtration with live rock and live sand is via bacteria, but I digress...

Believe what you want.
 
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Anonymous

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Chris:

No debate needed. We just disagree. Readers of the above two posts can decide for themselves.

What is important is varing views can be presented.
 

Fatal Morgana

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>...What is important is varing views can be presented.

Yes, here in RDO we do allow varing view to be presented and ask the reader to judge the merit of each of the views. However, this privlege can be abused to varing degree.
 

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