# How bad are high nitrates in a planted tank?



## touch of sky (Nov 1, 2011)

Nitrates are not a problem unless they get very high, but nitrites and ammonia should be 0. I would do a water change to reduce those.


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## Kylesaltandpepper (Aug 30, 2014)

Have you calibrated your API nitrate test kit because they're known for giving incorrect numbers. If not, check this out: http://www.plantedtank.net/forums/11-fertilizers-water-parameters/83545-calibrating-test-kits-non-chemists.html 
Other than that, high nitrates aren't that bad unless it gets to 150 ppm and over. Some fish can handle that and some can't.


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## redavalanche (Dec 7, 2014)

deconstructionalism said:


> I'm reading nitrates around 40-80 ppm on my API kit. The fish don't seem stressed in particular. Should I be worried about this?


Are you still getting good plant growth?


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## Diana (Jan 14, 2010)

If the nitrates are from fish food then there may be other things in the water that you want to remove. Do water changes, feed less. 

If the nitrates are from fertilizer you are over fertilizing.


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## Hoppy (Dec 24, 2005)

Diana said:


> If the nitrates are from fish food then there may be other things in the water that you want to remove. Do water changes, feed less.
> 
> If the nitrates are from fertilizer you are over fertilizing.


You either have to have far better color vision than I have, or most of the nitrate readings you get are at least 50% imagination, even if the test kit is still working right, and you are using the kit correctly. The best I can do with that kit is to say I have somewhere around 20-40 ppm, or 40-60 ppm, etc. It is a lot like measuring pH with an API style test kit. And, I'm not at all color blind.


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## Diana (Jan 14, 2010)

you could dilute the sample, 1 ml tank water + 4 ml RO, then multiply the test result by 5. 

I also cannot see the color difference beyond 40ppm. I do not bother trying to figure out what it really is. If it is in that unreadable range, I do a 50% water change, then test again the next day, ready to do another water change, if needed. 
Has not happened in a long time, though. Plants use up most of the nitrogen, and most tanks hover around 5-20ppm without me having to do much- low level dosing, and enough water changes to be able to clean the filter as needed.


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## Maryland Guppy (Dec 6, 2014)

You could use the 3 color approach.
Yellow it's time to dose.
Orange all is okay.
Red plan on a water change.


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## Diana (Jan 14, 2010)

As for the ammonia, I have seen a lot of posts from people who use Prime and test a trace of ammonia. The ammonia is locked up by the better quality dechlorinators, but some tests will still show it. 
Nitrite tests are usually accurate. I would simply keep up the water changes to keep it low until the bacteria finish growing. You could also add salt (sodium chloride, or other source of chloride) at the rate of 1 teaspoon per 20 gallons. This will stop the nitrite from crossing the gills and entering the blood system.

https://www.addl.purdue.edu/newsletters/1998/spring/nitrate.shtml


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