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.