My Ph was high at 8.0 and Alk 220. I put in a whole bottle of PH Minus, then ran the fountain HIGH for many hours on Sunday. It rained pretty shortly after I added the acid, and then again yesterday, and I had no idea what effect that would have. Today (Tuesday) Ph is back up to 7.8 (where it tends to like to be) and Alk is only 80!