Lately I’ve had an issue with rising PH. It tests over 8.2, I add the correct amount of Muriatic acid based on my TA (between 90-100) & it lowers it back down. Within a few days it’s up to at least 7.8 & rising. This is the third year of having the pool & i’ve never dealt with ph rising before this year. It has always stayed consistently around 7.5 all summer. What am I missing???