Could you elaborate a little more on why the Hannah checker can't distinguish?
I'm learning myself after a 20-year hiatus. We didn't have fancy electronic Checkers back in the day. The guy that maintains all the parameters at the store I buy corals from suggested that I pick up the HR nitrate tester. He said grab the HR as the regular nitrate tester is a headache or something like that. So I took his advice and ordered HR.
I'm like a sponge and am absorbing all this information I can possibly get from R2R and I'm always open to any constructive criticism.