Nitrate zero while feeding bioplus? I don't think so!
Bioplus and other powdered foods raise nitrates pretty high pretty fast.
I feed a tiny (and I mean tiny) pinch between my fingers of Bioplus once a week. Yes, nitrates are reading zero. I have no reason to doubt my nitrate tests because when cycling tanks readings go up when they are expected to. And yes, I'm shaking the solutions for the proper amount of time