I've tested with two test kits P234 & 5-Way HTH. Why am I getting two different alkalinity results with each test? Shouldn't the results be the same? HTH was 240 yesterday and 210 today. P234 was 190 yesterday and 160 today. Comparatively, the numbers went down the same amount from yesterday. However, I don't feel confident with the numbers and don't know how much more muriatic acid to add if I can't even start with "good" numbers! I'm inclined to go with Ben's numbers..... BTW...PH went up to 7.5...