High nitrite (NO2) reading after dosing nitrate (NO3)?

[drdripp]

I recently dosed my tank to 10ppm nitrate (had phosphates at 0.33ppm and nitrates at zero) by doing the math and using sodium nitrate in solution, in order to alleviate my nitrate bottleneck and get my chaeto to consume more phosphate. Although nitrates rose as expected, so did readings for nitrites (previously zero on weekly testing), tested a day after adding the sodium nitrate. Now API tests indicate around 0.25ppm nitrite. Could this be a false positive, or is my sodium nitrate contaminated, or something else? It has also caused some brown algae to grow, but I expected this.

I have a 5gal refugium with chaeto (has been growing).

Tank params:
SG: 1.026
Temp: 80.0 deg F
Ammonia: 0.01ppm
Nitrite: ~0.25ppm
Nitrate: 10ppm
Phosphate: 0.28ppm

 

[blaxsun]

Probably a false positive, but once your tank has cycled you don't need to really test for nitrites anymore. I'd ditch the API test kit and get a good nitrate test kit, ie: Salifert, Nyos, etc.

 

[Randy Holmes-Farley Verified Community Expert]

. Could this be a false positive, or is my sodium nitrate contaminated, or something else?

Could be either one, but there's no reason to worry about it, or even try to figure it out, IMO.

 

[drdripp]

Thank you both for your advice.