PH usually remains 6.8-7.0. Everyone thrives when it remains stable; though we know it sounds high for discus they are great and well acclimated when it is stable. We also check the PH in the tanks we buy any new discus from. We only have problems if our tank PH fluctuates too much or too often which I finally discovered was due to our R/O water vendor. I solved that problem by checking the new R/O while still in the bottles BEFORE doing water changes and, if needed, adding either Neut. Reg. or Discus Buffer (or combo) to water bottles and letting it adjust BEFORE we change water. It has helped stabilize.