Hmmm. I'm trying to use PoolMath to determine the amount of acid to add to reduce my TA from 285 to 80 in my new (still empty) hot tub but I must be doing something wrong. I enter 295, 7.6 for pH (both left and right boxes), and 285 (left box) and 80 (right box) for TA (TA values come from local utility, verified by my test kit). I then press Calculate and....nothing. I get NO recommendation for acid addition to lower TA. Anybody have any idea what I'm doing wrong?