I would look at the alk for the losses, not the PH. you have the opposite problem of 90% of people who have reefs. most of the time, the PH is to low. I would calibrate the PH monitor with a 7.0 souluiton and a 10.0.
Well my PH is finally dropping to 8.4 and rising to 8.7 and the end of the light cycle. My Alk has dropped from 11 down to 10. Pinpoint just sent me back a new Calcium probe and I calibrated it 3 times because I though it was off but nope my calcium really was 136.4 how I dont know but between last night and today its at 400 now I have no idea how it got that low no wonder why my sps and lps have been looking a little weird hopefully as I get my other things balanced my PH will follow on it own. My Mag was 1200 which I think is a little low so Im dosing some to get it to around 1380