I wouldn't start chasing ph if I were you. Keeping the big 3 in check, magnesium calcium and alkalinity, should be your goal. As well as maintaining a small amount of nitrate and phosphate
I prefer using Salifert test kits for my calcium, magnesium, and nitrate .
The Hanna handheld alkalinity had very consistent numbers compared to my lamotte alk test kit. I also use the Hanna ULR checker, it's supposed to be more accurate at the numbers we aim for
I'm going to suggest moving the GSP and Pom Pom to a isolated area. Unless you want all of your rocks covered with that.