Odd Nitrate Readings after dosing Sodium Nitrate

Tsquared · Jan 1, 2023

4-5 weeks back I managed to beat my hair algae problem but traded them for dinos. I bottomed out the nitrate and phosphates. I started dosing for both. At first, my Hanna tester and API test kit were very close. In the last week, the Hanna is 50ppm higher than the API. Would the sodium nitrate cause either of the kits to read falsely? I am about halfway through the Hannah reagent batch. Hannah reads 56.1 ppm and the API is between 5-10 ppm. I am using Modernist Pantry food grade branded sodium nitrate. I prefer the digital readouts due to color blindness/deficiency.

Miami Reef · Jan 1, 2023

Tsquared said:
4-5 weeks back I managed to beat my hair algae problem but traded them for dinos. I bottomed out the nitrate and phosphates. I started dosing for both. At first, my Hanna tester and API test kit were very close. In the last week, the Hanna is 50ppm higher than the API. Would the sodium nitrate cause either of the kits to read falsely? I am about halfway through the Hannah reagent batch. Hannah reads 56.1 ppm and the API is between 5-10 ppm. I am using Modernist Pantry food grade branded sodium nitrate. I prefer the digital readouts due to color blindness/deficiency.

Can you post a picture of the API results here (next to the card in white lighting)?

Randy Holmes-Farley · Jan 2, 2023

Tsquared said:
4-5 weeks back I managed to beat my hair algae problem but traded them for dinos. I bottomed out the nitrate and phosphates. I started dosing for both. At first, my Hanna tester and API test kit were very close. In the last week, the Hanna is 50ppm higher than the API. Would the sodium nitrate cause either of the kits to read falsely? I am about halfway through the Hannah reagent batch. Hannah reads 56.1 ppm and the API is between 5-10 ppm. I am using Modernist Pantry food grade branded sodium nitrate. I prefer the digital readouts due to color blindness/deficiency.

Nitrate is nitrate. Kits do not know where it came from.

One possibility is nitrite (as a contaminant in the sodium nitrate, or even by picking the wrong product: sodium nitrite) and a differential response from different kits to it as a false positive for nitrate from nitrite.