I use ma to lower my TA and get pH in check and have done so relatively well in the past. But I just purged and refilled the spa, lowered TA and have a problem. I thought something was wrong with my test kit because TA was getting really low but pH just was not cooperating. According to a store test TA is 44 and pH is 8.1. These numbers defy my understanding of TA/Ph balancing and past experience. Should I dump the water and try again? Why is TA not pulling down the pH?