api nitrate

Why is the nitrate test in the api testing kits always so of an inaccurate?? Shake it like crazy for one minute and it’s always the same results for nitrates extremely red which isn’t true at all. Would rather get the Hannah checker for nitrates only at this point.

So on one of my Facebook groups a guy mentioned he uses the API reagent in his Hanna nitrate HR checker. He was very vague and not helpful when I asked him follow up questions. Has anyone else done this with success? Getting 125 tests out of API for cheaper then 25 Hanna reagents seems like a...