[lakshen99]

I tested my water with api test and it shows around 80 plus ppm of nitrates... but my fish show no signs of any stress effects from it. Are api tests even reliable? I found this by Tom Barr and yes my nitrates come from KNO3.

I've kept the NO3 at 160 ppm for 3 weeks, no issues, as long as it is from KNO3, not over fed fish, dead fish etc......

So the answer is that the max level is actually quite high(over 100ppm NO3) if you are trying to kill fish with KNO3.

 

[jeffkrol]

Living in polluted waters: A meta-analysis of the effects of nitrate and interactions with other environmental stressors on freshwater taxa - PubMed

Nutrient effluents from urban and agricultural inputs have resulted in high concentrations of nitrate in freshwater ecosystems. Exposure to nitrate can be particularly threatening to aquatic organisms, but a quantitative synthesis of the overall effects on amphibians, amphipods and fish is...

pubmed.ncbi.nlm.nih.gov

 

[Asteroid]

As plantbrain stated, as long as nitrates are from dosed kno3 it shouldn't be an issue. I have nitrates in the 80ppm range many times in my setup between dosing and all livestock, including shrimp are fine.

 

[Aaronious]

I ended up with a tank above 200 nitrate levels. Nothing died, brought it down under 40 in a month. So if it gets up there, it shouldn't be harmful to anything. I wouldn't keep it at those levels personally.

These guys however seem to have a better understanding so if you're dosing, which I am not, there must be a reason to keep it that high on the right occasion.

 

[lakshen99]

hmm then i guess my shrimp died of other causes if my fish didnt show any signs

 

[Aaronious]

hmm then i guess my shrimp died of other causes if my fish didnt show any signs

oh, I didn't see you mention shrimp. Shrimp are more picky and it possible they died from high nitrates. But I am no shrimp expert, I have only been dabbling in the shrimps.