high nitrate level

[george2481]

my nitrate level is high in my salt water tank and I can not get it to go down. I have tried to lower it by adding prime and I did a water change in sunday, but it still seems to be high. What can I do to lower it?

[SBreef]

What is your nitrate level?
What size system? What kind of filter system? What are your other perameters?

[CD]

Welcome to MAAST, George!!

On top of the questions that Roy asked you (above), how long has your system been running? The more info you can give us, the easier it will be to pinpoint the problem(s) and help you. ;)

W. :)

[GaryP]

Welcome to MAAST George.

Let me give you some basics on how nitrate levels get "high." What most of the "filtration" equipment in a system is designed to do is process nitrogenous waste to produce nitrate. This includes wet/dry and biowheels and even Live Rock. The problem comes when there is not sufficient environments available to the type of bacteria that take the nitrate and process it further to complete the nitrogen cycle. This step is denitrification. These bacteria grow in areas of the aquarium with low oxygen levels. These include the deep pores of live rock and in deep sand beds. When I say a deep sand bed, I am referring to at least 4" of sugar fine sand. The larger the particle size in a sand bed, the deeper the bed needs to be. I personally prefer using a 4" bed of sugar fine sand with 1/2 - 1" of special grade sand on top of it to keep it from blowing around.

As the oxygenated water percolates down through the sand bed, other types of bacteria use up the oxygen in the water. By the time it gets down to the lower layers of the sand bed the oxygen levels are low enought that the denitrifying bacteria are able to survive and grow.

Your other option for reducing nitrates is a refugium. A refugium is a seperate tank that contains a deep sand bed as well as provides a place to grow macro algae. The algae use the nitrate like fertilizer and it is converted into new algal growth. A combination of a deep sand bed in the main tank as well as a refugium is ideal for limiting nitrates in the system.

I hope that was helpful.

[v2k]

I used biospira succesfully, which you can buy in a pouch.

[GaryP]

Biospira is a good product, but unless you have an environment for the bacteria to grow it not going to help nitrates.

[Tim Marvin]

I have had great luck with the refugiums. My nitrates were undetectable. If you don't have at least an 80-100g tank the deep sand bed probably won't work very well, like a nano. Gary gives excellent advice on water chemistry.

[GaryP]

Aw shucks, thanks Tim.

[deast7]

Gary

Thanks for the explanation -- I have a 100g tank with approx 3 inch live sand, 85 #'s live rock, 15g wet/dry sump, Red Sea skimmer (the tank is almost 9 months old and all of this was recommended to me from a local LFS when I started into this hobby 9 months ago). I use RO/DI for all water changes and topoffs. I have 4 green chromis, a pair of gold/maroon clowns, a butterfly and numerous cleaners. I also have a couple of mangroves in my sump. My nitrates have consistently hovered around 20 ppm. My question is how do I lower my nitrate level to the 0 mark without tearing the system apart? BTW, everything in my tank appears fine and healthy and eating well. I feed once per day and only enough that they can eat in about 3 minutes ( they always come right to the turkey baster at dinner time -- sometimes pulling food from the end). Thanks for your help.

Cheers,

Dave

[GaryP]

Dave,

What particle size sand do you have? Sugar, Special grade, or course? I think you probably need some deeper sand in either case. Even if it is sugar fine, 3" is not enough to generate an effective anoxic layer for denitrifying bacteria. You might also want to consider adding some chaetomorpha to your fuge, in addition to the mangroves.

Here's another idea for you. Do you have the lights to put clams in the tanks? Clams are sometimes used as nitrate scrubbers.

Is this a fish only tank or do you have corals as well?. Nitrates aren't really an issue in a FO tank.

There is another approach as well. If you pull out as much of the nitrogenous waste as possible with your skimmer, it never has to go through the nitrogen cycle. You may want to make sure you are getting everything out of your skimmer or even look at upgrading your skimmer. Skimmers often need to be tuned.

Using carbon as well as physical filtration can also be helpful. Again, its a matter of removing the waste before it breaks down and enters the nitrogen cycle. Do you have a filter floss on your wet dry? If so, do you clean it regularly. If you don't, the solids caught there can decay and contribute to the waste in the system. I would recommend cleaning or replacing filter floss at least once a week.

[gjuarez]

Yup, what Gary said.

[hammondegge]

i experienced a similar problem a while back. nitrate just seemed to stay a little higher than i wanted it no matter what i did. i put a bag of 1/2 carbon, 1/2 kent nitrate sponge in the sump. this along with heavy macro export, and removal of all filter media did the trick.

[deast7]

gary

Thanks for getting back to me - I'll look into some chaetomorpha for the sump. It is a FOWLR and I don't currently have the lighting for clams (always willing to consider some if anybody has some they would like to part with). I am not sure the sand type (when I was getting into setting up the tank -- long before I knew of MAAST - Texas Tropical sold me what they said I needed to set up a FOWLR 100 gal tank -- so, whatever they sell, that's what I have -- doesn't appear to be the finest sand out there so probably course or special grade.) I have turned the skimmer up and am now producing a lot of junk, (much more than before). I have been alternating a carbon filter and that blue filter Texas Tropics sells and changing it out every 2 weeks -- may need to change it out every week -- also running a bunch of bio balls. Thanks again -- just a newbie trying to get the knack of this saltwater thing and trying to learn from others.

Cheers,

Dave

[Richard]

also running a bunch of bio balls


I would pull out the bioballs. You don't need them since you have 85 lbs of liverock and they can lead to elevated nitrates.

[matt]

The bioballs are probably not helping. How are you lighting the mangroves? They like alot of light; difficult to light that much in a 15 gallon sump/refugium without causing some heat problems. The live sand they sell is not the finest grade, but will do okay. You might try adding more live sand over time to bring your sand bed depth to 4". Most importantly, though, you'll need to stock this live sand with bristleworms and other sand dwelling animals to keep the sand moving and healthy. They eat bacteria in the sand which allows more to grow, thus processing more nitrate. You can get sand bed "recharge" kits from IPSF or inland aquatics, or maybe get someone in MAAST to give you some "real" live sand, that is sand with lots of worms and micro-critters. Try this approach first, and don't add anything like sifting stars or burrowing fish; they'll just eat the animals you need to have in the sand.

At some point if you have a nitrate build up you're going to have an algae bloom; probably you've already had one at some point. BTW, 20ppm nitrate in a fish only system that's 9 months old is not too bad. Get your sand bed going, and it will come down over time. Eventually you might think about losing the wet-dry in favor of a large capacity refugium, where you could grow caulerpa as well as the mangroves. That will really help process the nitrates, and some phosphates, out of your system.

[::pete::]

Welcome George!!!

[carlinsa]

i have everyone beat ask scuba steveo and donnsa my nitrates were at 160++++ it was darker than the 160 on a salifert test. i tool the bio balls out of my wet dry put in cellpore i got from finaddict and added a fuge. my nitrates are down to around 40ish but i have a very well stocked 135 pred tank. i did some monster water changes and stirred up the sand every few days and changed the pad in the wet dry every couple days to help and so far it has worked for me.

carl

[deast7]

Hey Guys

Thanks -- the bio balls are gone today. If anybody out there has any "Real" live sand with good critters I'd love to talk to you -- I'm lighting the mangroves with a small silver lamp and bulb recommended from Fin Addict (the sump and lighting are located in the base cabinet). When I decide to drop the wet/dry and go with the fuge what would be the recommended size? Sounds like I'll be slowly adding some additional sand. Thanks again.

Cheers,

Dave

[GaryP]

I would pull out the bioballs. You don't need them since you have 85 lbs of liverock and they can lead to elevated nitrates.

Richard, you should be ashamed of yourself. The LR leads to high nitrates too, should he pull that out? The bacteria on the glass leads to high nitrates, so no glass either? The bacteria in the plumbing leads to high nitrates. No plumbing either? The same for the aerobic layers of live sand. So, the only way to eliminate nitrates is to not to have an aquarium at all.

I realize I am being more than a little bit of an ***** here and I apologize. My point is that I feel the role of bioballs in high nitrates is not what most people think it is. What is the alternative to the production of nitrates? Leaving it as nitrite and ammonia? I doubt that anyone would agree with that as a viable solution. High nitrates has nothing to do with how they are being produced, but rather with the fact that there is a biological dead end once they are produced. There is not satisfactory dentrification capacity to process the nitrate into nitrogen gases.

[alton]

In the early 90's I had a 135g with a Clown, Undulated, Niger, Pinktail, Huma Huma, and Rectangles triggers. I think I mispelled the last one. You can't get a more Bio Load than this. Nitrates never went over 80, most of the time they stayed btween 40 and 60. And that was with a water chage once every three months if they where lucky. If your Nitrates are going over a 100 something has to be dead in your system?

[alton]

Hey this sure beats the old Oceanic Salt arguement. Maybe we should start a new thread "Bio Balls" to use or not to use? And never forget the famous "Bio Bale" that started it all. I love this website!

[GaryP]

Gary, I think the key about the whole bio-balls nitrate thing is the proximity, or lack there of, to a good anaerobic zone. If the rock churns out nitrates it's very near the internal area of the rock where the oxygen levels are lower. Maybe I'm off, but that's always what's in my head.

Joshua, in this case he has lots of LR and has high nitrates and its obviously not working for him. The aerobic area on the surface of the LR and the interior spaces where they might be anaerobic bacteria aren't really that close in a tank with turbulent flow. The problem with using LR as your primary site for denitrification is porosity and flow. If there is a lot of low, then chances are the water isn't going to have a very low O2 concentration. If its too porous you have the same problem. I know some denitrification takes places there but I have seen a lot more tanks with nitrate levels without a good sand bed then I have with one.

While there isn't that great of flow in a sand bed there is another factor that applies call diffusuion. Porosity is not an issue in a sand bed that is set up correctly and the nitrate ions will flow into an area of lower concentration, even if the water doesn't move. The ions will try to maintain a continuous concentration throughout the entire volume of water. If nitrate is being removed by the denitrifying bacteria, this acts as an "ion pump" that sucks nitrate into the sand bed. Also, nitrogen bubbles leaving the sand bed will pull water downward.

The thing that no one even discusses in regard to bioballs is what else is it doing for your water quality. There really isn't a good test for dissolved organics but if there was I would be willing to bet that they are doing a lot of the work in removing them as well.

[GaryP]

If you remove the balls perhaps the aerobic bacteria will colonize much more on the rock and therefore spend less time in the water column trying to find anaerobic bacteria to eat it?

Those pesky nitrates are so impatient. :)

[deast7]

OK -- I'm catching pretty much most of this discussion so, therefore, to bio ball or not to bio ball, that is the question? Thanks.

Cheers,

Dave

[v2k]

Matt, Are you saying a refugium can serve as a substitute for the wet dry filter?I would assume then one runs the refugium simultaneously for a while before giving up the wet dry trickle filter? If I have a 29 gallon tank, what size refugium would do the work of the wet/dry filter?

[Richard]

Richard, you should be ashamed of yourself. The LR leads to high nitrates too, should he pull that out? The bacteria on the glass leads to high nitrates, so no glass either? The bacteria in the plumbing leads to high nitrates. No plumbing either? The same for the aerobic layers of live sand. So, the only way to eliminate nitrates is to not to have an aquarium at all.


Aw man! I can't believe I missed this one. Could of been a fun debate. Gary, were you in a bad mood that day LOL.

As Gary so err...kindly :unsure ...pointed out, there is plenty of surface area for nitrifying bacteria to grow on in a reef tank. That is why I don't think there is any reason to have them in a reef tank.

Bioballs do not directly lead to higher nitrates. The problem comes from the fact that bioballs are perfectly shaped to accumulate detritus over time. So unless you always to a very good job of prefiltering the water, you will eventually create a nice nutrient sink which can lead to variety of water quality issues. This will also have the effect of lowering your ORP substantially which then leads to further water quality issues.

IMO, bioballs are not worth the trouble and your better off without them.



The thing that no one even discusses in regard to bioballs is what else is it doing for your water quality. There really isn't a good test for dissolved organics but if there was I would be willing to bet that they are doing a lot of the work in removing them as well.


I have to disagree with you on that one Gary. I don't know of any mechanism by which dripping water over plastic would lower dissolved organics. I know the exact opposite will happen if they become a nutrient sink and lower the ORP as I mentioned above.

[NaCl_H2O]

Well, my tank has balls! :P

[Richard]

Doesn't your tank have EVERYTHING? ;)

[bigdscobra]

Well, my tank has balls! :P


Mine too and Iam keeping them. :lol

[NaCl_H2O]

Doesn't your tank have EVERYTHING? ;)

No, it doesn't have Nitrates ;) ;)

[Richard]

No, it doesn't have Nitrates


LOL, Good one. Neither does mine.

[gjuarez]

I love this type of thread, where two aquarists with lots of knowledge debate. I feel it is when I learn the most. Keep it coming, wheres Gary?

[NaCl_H2O]

To be honest, my fuge probably has more to do with my water quality than the Bio-Balls.

When I put this system together I just put in some of everything that worked for me so well in my 125g and added to it. The way I figure it, all of these things contribute in some way to the chemical/ecological balance and I doubt that any of us fully understand how they interact as a "System". I do have a very large wet/dry filled with Bio-Balls and mechanical filtration (floss). Also have a large fuge with a DSB, and a DSB in all the tanks, plus a VERY generous supply of live rock, lots of sump space, and an aggresive skimmer. Bio-load is reasonable, but not heavy, I feed as little as I can get away with, and do 20% water changes every two weeks.

Richard's peleted Charcoal bed fuge is intriguing! I have considerd changing my small frag tank into one of these?

[bigdscobra]

I feel the same way,

I have a fuge that is jammed pack with cheto and a wet/dry above my sump. Also two biowheel filters that I use to add carbon W/O the wheel. A little bit of every thing seems to work great. Now only if I had a chiller ;)

[matt]

Matt, Are you saying a refugium can serve as a substitute for the wet dry filter?I would assume then one runs the refugium simultaneously for a while before giving up the wet dry trickle filter? If I have a 29 gallon tank, what size refugium would do the work of the wet/dry filter?

The wet/dry filter is kind of a dated type of filtration; it's designed to provide habitat for denitrifyng bacteria that would normally not exist in an "old style" salt water aquarium with no sand bed or live rock. It also does a good job of aerating the water. But, if you have lots of live rock, a decent sand bed, strong water flow, and a skimmer, you don't get any benefit from the wet/dry, as you have created the environment in your system that does all the things it would do, in a more thorough manner.

The wet/dry, or more specifically, the bioballs in it, does not "create nitrates" but, if it's the primary type of bio-filtraton you have, nitrates will tend to accumulate because you don't have low oxygen habitat for the bacteria that process nitrates into free nitrogen. (There used to be some sort of anaerobic filter for that, too) This is where the sand bed, and refugium, can really help.

The refugium simply acts as a habitat for growing macroalgae, which will consume nitrates and phosphates from your tank. It also provides habitat for lots of small animals and larvae, which then get picked up in the water flow and delivered to your tank, where they can be eaten, thus lowering the amount of food you have to add to your tank. Plus, if you run the lights on a reverse cycle, the macroalgae photosynthesize at night, keeping O2 levels up in your tank and helping to stabilize ph.


You probably can easily convert your wet/dry into a refugium, simply by removing the bioballs, keeping the water level in it nice and high, and putting some sand and live rock in it. You'll need to light it, of course; power compacts work well for that. Once it's set up and stable, you can grow macroalgae like caulerpa. If you have a well stocked tank, probably the caulerpa will grow really fast. Then you periodically harvest it, and in this way remove the nitrates and phosphate from your system.

For a 29 gallon tank, a 10 gallon tank would work fine as a refugium, or better yet, a 20 "tall", if you don't want to try to convert your wet/dry. It doesn't really matter; just get a decent water volume and good light.

Hope this helps

[matt]

Oh yeah, I forgot one thing. If you're currently using bio balls, you should remove them gradually to make sure that you give the bacteria time to colonize on the live rock and in the sand. Removing all of them at once might put your tank into a nitrogen cycle, which would really suck for the animals. If you have lots of live rock and a fairly mature tank, it might not make any difference, but probably it's best not to risk it.