High nitrates no matter what I do

[Eleni18]

Hello all. I am fighting a constant battle with high nitrates which I cannot seem to lower whatever I do. I do regular 10-15% water changes every 2-3 weeks at the most, I run carbon and a polyfilter, as well as a skimmer, and for the past 10 days I have a mesh bag with API Nitra-zorb in a low flow area in the tank. My nitrates are stuck to around 20, no matter what I do. I have a 75 gallon mixed reef tank with lps and soft corals and fish. Is there anything I can do to reduce my nitrates or should I not worry too much about 20? All fish and corals seem OK.

 

[Dbichler]

I wouldn't worry too much about twenty nitrates with your current stocking. Increase to weekly waterchanges of higher amount if you start seeing any negative impacts.

 

[SPR1968]

If your tank is running ok your fine at 20ppm nitrate, that’s we’re mine has been for years and won’t budge do to the massive bioload I have.

If you do want them to lower, your could change to 10% weekly water changes, increase your biological filtration (Seachem Matrix etc) or look at carbon dosing like Nopox.

But if everything is ok I would leave it alone, and in the meantime research the different methods in case there needed in the future.

 

[boacvh]

Just a thought but have you checked if test is perhaps faulty? when I started my tank I had a similar issue that turned out to be a faulty test kit.

 

[Eleni18]

Just a thought but have you checked if test is perhaps faulty? when I started my tank I had a similar issue that turned out to be a faulty test kit.

Salifert NO3 test

 

[boacvh]

Salifert NO3 test

That's the same one I use. But I had a bad box I believe. I purchased a new one and started getting different results

 

[Slawman]

Hi Eleni,

I have used biopellets to effectively reduce Nitrates. I have also removed the sand from my tank which had a big impact on reducing Nitrates. Are you keeping SPS? 20 is not too bad for softies and fish.

Is your skimmer working well? Sand beds and foam filters can become nitrate factories. I would also try some larger more frequent water changes, say 25% each week.

 

[Jake_the_reefer]

I've had a tank hold 40 nitrates constantly. Water changes weren't helping or anything. Then one day my nitrates dropped to 3 and have held steady there. I'm running a junk 10$ skimmer that barley works. What I'm thinking is that nutrience was leaking from organics in my rocks

 

[clm65]

Use your test kit to test some newly mixed salt water. If you get around 20, then either your water is a source, or more than likely, your test reagents are bad.

 

[beaslbob]

I don't think that is all that much to worry about.

FWIW water changes will limit nitrates but not reduce them to unmeasurable levels.

That said nitrate consumers like macro and other algae will bring them down. But even that is not quarantined. It is very possible that the algae could be consuming ammonia and forgoing nitrates for nitrogen. Once the bacteria start consuming the ammonia, then nitrates will drop.

my .02

 

[MarineMalecki]

+1 on the test kit. I had a similar issue, but with my Mg. Results kept reading low so I kept dosing more to raise - on a 600G system, I very quickly had too much. I did an ICP test and my Mg was almost 2000

 

[Eleni18]

I've had a tank hold 40 nitrates constantly. Water changes weren't helping or anything. Then one day my nitrates dropped to 3 and have held steady there. I'm running a junk 10$ skimmer that barley works. What I'm thinking is that nutrience was leaking from organics in my rocks

How do you mean? I have quite a lot of live rock

 

[Eleni18]

I don't think that is all that much to worry about.

FWIW water changes will limit nitrates but not reduce them to unmeasurable levels.

That said nitrate consumers like macro and other algae will bring them down. But even that is not quarantined. It is very possible that the algae could be consuming ammonia and forgoing nitrates for nitrogen. Once the bacteria start consuming the ammonia, then nitrates will drop.

my .02

Thanks...So you think it's a question of the right timing.

 

[Eleni18]

Use your test kit to test some newly mixed salt water. If you get around 20, then either your water is a source, or more than likely, your test reagents are bad.

Thanks! Good Idea!

 

[beaslbob]

Thanks...So you think it's a question of the right timing.

Don't know about timing but what happens with water changes is the tank builds up to where the nitrates (and other things that change) are removed by the water changes. For instance, if you change out 1/10 or the water the tank builds up to 10 times the change between water changes just before a water change. then down to 9 times and back up to 10 times the change before the next water change. Plus whatever is in the replacement water.

Which is why we have to dose thing like calcium, alk, and magnesium even tho we are doing water changes.

But if you have macro or other algae consuming nitrates, and the tank bacterial is consuming ammonia, nitrates will be 0 regardless of the water change schedule. And even any nitrates in the replacement water.

my .02