What is the reasoning for sodium nitrate not showing up on the hanna checker? I was dosing sodium nitrate and it was not showing up on my hanna test. But it would show up perfectly on api. So I bought the hanna calibrated bottles. My checker read it just fine. So I did a test last night. I dosed .7 grams of sodium nitrate to 2.5 gallons of new saltwater. 12 hours later I tested with api and hanna. Should read around 38. Hanna read 1.2 and api exactly 40. What on earth is going on? @Randy Holmes-Farley, do you know the chemistry behind this?