High Nitrates

[dan_chng]

Hi everyone,

My 80 gal tank has cycled and it has been setup for at least 2 months now. Ammonia & Nitrite is zero but I noticed that my Nitrate is now at 25 and climbing. I am now using Corallife nitrate remover but it doesn;t seem to help.

I have corals and fish in my setup. Can anyone suggest ways to help reduce control nitrate? I even have setup with a deep sand bed and life rocks. I am also using some bio-rings in my sump, not sure if it is causing high nitrates??

Thanks

 

[jlm]

According to what I've read, bio-balls, rings, whatever, in the sump has fallen into disfavor because it basically constitutes a nitrate factory. You might try replacing the rings with some caulerpa and a light 24/7.

Extra water changes might help get it back under control short term.

 

[Anonymous]

Welcome both of you to reefs.org!

It is a common myth that bioballs and other media upon which benthic nitrifying bacteria are "nitrate factories". It discounts the science behind the oxidation of ammonia and resultant nitrogenous wastes, or simply demonstrates a poor understanding of the nitrification process that absolutely must be achieved in captive systems.

There will only be "high" levels of nitrates because ammonia must be oxidized. The ammonia simply cannot be avoided, and nitrification MUST occur. Also, know that Caulerpa spp. can be TRICKY to deal with, especially for those unfamiliar with this macroalgae's behavior and life cycle. Its nutrient fixing abilities (and those of other macroalgal forms) is harnessed to help control many other nutrients besides those of nitrogenous composition (for instance, phosphorous), achieved directly by harvesting said macroalgae (and with Caulerpa, this MUST be done a certain way-by pruning from the "root", not just cutting back-or you'll ensure death or the good likelihood of setting it off on "going sexual")

I would advise one of two things (you could go with both, but ultimately one would rather undo the effects of the other), foam fractionation (a.k.a. protein skimming), to be achieved before the water passes through the bio-media, and/or refugium in which you would install a deep sand bed to achieve denitrification. Searching our library at http://www.reefs.org/library as well as the Advanced Aquarist database, and http://www.wetwebmedia.com (use the Google feature to quickly find specific information on both) will garner you MUCH information on controlling high nitrate readings.

 

[Len]

test bump

 

[ChrisRD]

Thanks Len - the missing thread reappears!

It is a common myth that bioballs and other media upon which benthic nitrifying bacteria are "nitrate factories".

I basically agree. IMO it's more of a misunderstanding than a myth, because use of these types of filtration methods can result in high nitrate readings (if they're neglected). I agree that the cause is really not directly related to the aerobic bacteria colonies they support. IMO, one of the reasons the use of bioballs and other plastic filtration media has fallen out of favor with experienced aquarists is because they create additional maintenance chores. It's possible to use them and maintain low nitrate readings - I've done it - but IMO it's more work. IMO they suffer from other shortcomings as well, but that's another topic...

The problem is that any media or filter that can trap detritus needs to be cleaned frequently, or it can ultimately lead to a degradation of water quality. The crud that collects in/on them starts to decompose, thereby resulting in more phosphates and ammonia (which is then very efficiently converted by said filter to nitrite and ultimately nitrates). The end result of this can be high nitrate levels and nuisance algae growth.

HTH

 

[Anonymous]

The problem is that any media or filter that can trap detritus needs to be cleaned frequently, or it can ultimately lead to a degradation of water quality. The crud that collects in/on them starts to decompose, thereby resulting in more phosphates and ammonia (which is then very efficiently converted by said filter to nitrite and ultimately nitrates). The end result of this can be high nitrate levels and nuisance algae growth.

Absolutely, and this is going to be an issue no matter what form of filtration you take (unless you live in a tropical country and have an open system, but how many are that masochistic?). My basic point is that, unless you're willing and able to utilize what I would consider the best thing, which still requires a degree of maintenance, you must utilize some means of nitrification. This can be most simply achieved via undergravel filter, which, as with any other form we can speak to, will also require maintenance. I've found that setting up a wet/dry, with foam fractionation occurring before the "to be filtered" water hits the tower, and good (and easily accessible) mechanical filtration coming post-skim/pre-bioball is relatively easy to keep up with.

On the other hand, I'm sure you know that I'm a big fan of natural systems, and the use of refugia and deep sand bed methodologies (in which cases I like to see the system go sans foam fractionation), but as has been discussed before, this may not be the best route for many (if not most) new hobbyists.

 

[ChrisRD]

this is going to be an issue no matter what form of filtration you take

Actually, no - IME it's not a problem in a system that has good circulation and uses live rock, live sand and a skimmer for filtration. There's no place for detritus to get trapped.

Further, live sand and live rock also have the ability to provide denitrification - something wet/drys and undergravel filters don't.

I ran a fish-only tank for years with live rock, a thin (aesthetic) covering of sand on the bottom and a protein skimmer with virtually no maintenance for over a year at a time. No water change, no vacuuming, nothing. Fish were fed every day and evap was topped off. Skimmer cup emptied once a week. That was absolutely it. Nitrate levels were never detectable on various kits or by the LFS.

I've setup FOWLR tanks for others the same way - similar (almost no maintenance) situation - same results. Try that with a wet/dry or an undergravel filter setup and see what your nitrate readings are at the end of the year.

Anything can be made to work to some extent, but what's the point? Would you ever actually recommend someone setup a modern reef tank with a wet/dry or an undergravel filter?

 

[ChrisRD]

I have corals and fish in my setup.

How many fish (size, species, etc.)? How heavily stocked is the tank? Hopefully not very at only 2 months.

I even have setup with a deep sand bed and life rocks.

Are you using a skimmer? If so, what kind? If you have adequate amounts of live rock, live sand and a decent skimmer you have all the filtration you need to maintain good water quality.

I am also using some bio-rings in my sump, not sure if it is causing high nitrates??

IMO, most likely the bio-rings aren't doing much either way. I'd ditch them because they're not needed but, unless they've gotten gunked up with detritus that's probably not the source of the problem.

Are you adding anything besides food to the tank?
Is your source water for top-off and water changes nitrate free?

 

[dan_chng]

I have corals and fish in my setup.

How many fish (size, species, etc.)? How heavily stocked is the tank? Hopefully not very at only 2 months.

[dan_chng] I have 5 fishes sizes from 1 in to 4 in and my tank is actually 4 mths now (my mistakes stating 2)

I even have setup with a deep sand bed and life rocks.

Are you using a skimmer? If so, what kind? If you have adequate amounts of live rock, live sand and a decent skimmer you have all the filtration you need to maintain good water quality.

[dan_chng] Yes I am using a venturi skimmer which accoring to specs can handle up to 300 gal. I am not using live sand but crush coral sand.

I am also using some bio-rings in my sump, not sure if it is causing high nitrates??

IMO, most likely the bio-rings aren't doing much either way. I'd ditch them because they're not needed but, unless they've gotten gunked up with detritus that's probably not the source of the problem.

Are you adding anything besides food to the tank?
Is your source water for top-off and water changes nitrate free?

[dan_chng] I am adding corallife's trace elements 7 calcium other then food, as for top up water, I am using filtered water (not R/O), will check and see if there is any trace of NO3 it there. As for bio-rings, I have sponges for mechanical filteration b4 bioball, so not much detritus in bio ball. If I shld ditch bioballs/rings, shld I do it all at once or bit by bit?

 

[ChrisRD]

I would start by checking out the filtered water you've been using. That could be contributing to the problem.

Also, the crushed coral substrate could be part of the problem too. Are you vacuuming it regularly? It has a tendency to trap detritus. If you don't want the maintenance task of having to keep it clean, I'd recommend removing it and replacing it with either about 1/2" layer of "medium" grained sand (say 1 mm to 2 mm) or a 4+" bed of fine grained sand (say .2 mm to 1.2 mm). If you stay with the CC substrate, make sure you have plenty of circulation in the main tank and stir/vacuum the crushed coral often to prevent detritus bulid-up.

If you're prefiltering the water going through bio-rings they're probably not the problem, although IMO they're still unnecessary. If you remove them, I'd do so gradually, and then ditch the mechanical (sponge) filtration too. Again, if you decide to stick with this system, make sure you're keeping those sponges clean.

Another thing to watch out for is foods. If you feed a lot of frozen foods, try defrosting the food in warm tapwater and then dumping it through a fine mesh net before putting it in the tank. This gets rid of the high-nutrient juices and allows you to feed your fish more without developing water quality problems.

HTH

 

[Anonymous]

Protien Skimming,Liverock.....and water changes. Thats it. Algae scrubbing works great too......but you will need a refuge.

 

[Anonymous]

Speaking only from my experience:

I had a huge nitrate problem that all the skimming in the world wouldn't stop. At times it was up to 40ppm and I did weekly and even by weekly water changes that were from 20-30% of the tank volume. No help. I took the advice of people that said to lose the bio-balls in my wet/dry, so I slowly removed them over the course of two or three weeks and there was absolutely no change in my water chemestry. The LR was still producing the nitrates.

When I moved tanks, I added some more LR to the tank and addes some to the sump (really dead limestone, but within two months it was full fledged LR).

I decided to put the bio-balls back, but this time into the built in overflow. This was mainly so I could reach the filter pad I shove in there, if not it would be way at the bottom. Low and behold, my nitrates have been absolutely zero ever sinse.

I have a 1/2 inch sand bed so no DSB, but my sand bed produces bubbles all the time, which I assume are nitrogen gas.

I credit the bio-balls in the overflow for the low nitrate levels. I think the lack of air circulation caused by the filter pad crammed over them is creating anoxic patches that help denitrification...maybe not though.

My LFS guy has the same tank with bio-balls in the overflow and he also has zero nitrates...his tank seems WAY overstocked to me as well.