Question How much nitrate is ok

Mii

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So I know nitrate is much less toxic than ammonia and nitrite, but it can still be toxic in large quantities. And I was wondering how much of it is ok before you negativity impact the fish's health?
 
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Mii

Mii

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BluMan1914 said:
Most will say up to 40ppm is fine.
If you are doing regular maintenance, nitrAtes should not even be a concern.
I was wondering if I could use nitrates to tell if I'm overstocked or how many more fish I can have in a tank. Like add fish gradually so there isn't ammonia and just look at the amount of nitrate to see if I can safely add more.
 

BluMan1914

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Dont worry about the nitrates, or ammonia as long as you are doing regular maintenance.
I rarely test my water, and I dont worry about nitrAtes, or ammonia because I do regular water changes. And I do 75-80% water changes.
If you are worried about stocking, your filter, size of tank, and the type of fish you want, will be more of a determining factor for your stock.
 

RomanNoodles96

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Mii said:
So I know nitrate is much less toxic than ammonia and nitrite, but it can still be toxic in large quantities. And I was wondering how much of it is ok before you negativity impact the fish's health?
I'd say 40ppm as anything higher would probably start killing inverts. When my water hits anything above 40ppm I know its wc time. If you have little to no nitrates in your tap and you have plants I wouldn't worry at all.
 

jake37

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Depends on the fish. 40ppm is what a lot of folks say for common fishes (guppies and such). But there are more delicate fishes like Discus that require cleaner water.
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Truth be told i've heard of guppies doing fine in 80ppm nitrate.
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My target for my 4 tanks is below 20ppm and i would say they average around 10 or 15 most of the time.
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You would have to dig out some scientific papers where they have done control studies to actually determine when or if nitrate has an impact and even then it would only be relevant to the specific species they studied. 99% of what people say (including me) is just hersey and not backed by any conclusive evidence.
 

86 ssinit

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I’m all for the 40 ppm. But remember nobody checked for nitrates till some time in the 2000s. My 2003 api master kit didn’t even come with it. And the new test is as accurate as any guessing game. From 20 to 180 all look the same. If you change water weekly 30-50% you won’t have to worry.
 

jdhef

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Apparently there are many member here in the UK who have 40ppm of nitrate in their tap water, so their nitrate is never under 40ppm. While you want to keep nitrates under 40ppm if possible, I think the bigger problem is large swings in nitrate levels. Like for example if your tank had a nitrate level of 100ppm, your fish may adapt and be doing fine, but then a large water change using water containing 0ppm of nitrate would bring the nitrate levels down so (once again, for example) 10ppm. That would be dangerous to your fish.

So if you have 0ppm in your tap water, and kept your nitrates under 40ppm, a 50% water change would only result in lowering the nitrates to 20ppm, which fish can handle.
 

RomanNoodles96

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jdhef said:
Apparently there are many member here in the UK who have 40ppm of nitrate in their tap water, so their nitrate is never under 40ppm. While you want to keep nitrates under 40ppm if possible, I think the bigger problem is large swings in nitrate levels. Like for example if your tank had a nitrate level of 100ppm, your fish may adapt and be doing fine, but then a large water change using water containing 0ppm of nitrate would bring the nitrate levels down so (once again, for example) 10ppm. That would be dangerous to your fish.

So if you have 0ppm in your tap water, and kept your nitrates under 40ppm, a 50% water change would only result in lowering the nitrates to 20ppm, which fish can handle.
I'm pretty sure nitrate shock was disproven, but I could be wrong.
 

AvalancheDave

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The 96-hr LC50s for adult fish are all in the 4-8,000 range.

Younger stages (especially fry) and cold water fish (salmonids in particular) are less tolerant.

The best study is probably where salmon were grown from 100 to 1,200 grams over 8 months in 44 (10 mg/L nitrate-nitrogen) and 443 ppm nitrate (100 mg/L nitrate-nitrogen). Health, feed conversion ratio, and mortality were the same between the two groups.

I've started looking into dissolved organic carbon and it seems to be much worse than nitrate with growth suppression starting at levels ~20-30 times lower. It's also much more highly correlated with disease.

RomanNoodles96 said:
I'm pretty sure nitrate shock was disproven, but I could be wrong.
I don't think it's been studied but nitrate can reach levels where there's many more nitrate ions than those that determine water hardness. That might result in osmotic shock if a water change is done too quickly.

But a fish won't be shocked if it suddenly stops ingesting nitrate (yes, that's the way nitrate gets into fish).
 

mimo91088

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I get depression and sometimes I ignore my tanks for too long. I've had tanks literally off the charts in the past. No ill effects on fish or snails. 40 is a good goal like everyone has said. But if you go over it's not a huge deal. Just change some water and you're fine.
 

Redshark1

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Maximum nitrate allowable in the tap in the uk is 50ppm.

Nitrate is behind a lot of algae blooms so its a good idea to keep it low if you can.

I aim for orange on the API test, not red.
 

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