Im having an issue with low ph, down to 7.6 so I add bicarbonate slowly till I reach my usual reading 8.0-8.3, but I notice that my coral become stress ended up for my one coral to died.
The best way to increase your pH natural is to attach a tube in your skimmer air intake and take air from outside or otherwise get some CO2 scrabber, additional you can also add air stone to your sump. This will naturally increase your ph to 8.0-8.4 and if higher/lower it will down to the correct reading.
A CO2 Scrabber
Skimmer taken air from outside