I have a salt system. I check the chemicals once a week, typically:
-calcium hardness 200-225
-cyanuric acid 30
-free chlorine 2.0
-salt is 3000 PPM
I need to add at least 2-3 lbs of dry acid (sodium bisulfate) WEEKLY to get the pH down. I also use a water clarifier every week (about 8 ounces), and an algaecide (copper based) about 4 ounces a week.
I suspect the salt is eroding the plaster as the plaster feels "pitted" and creating an alkaline water situation. Note that the pool plaster is original, at 14 years old.
I appreciate any expert thoughts on the chemical balance and the rational behind why the pH keeps going up. The pool water is always clear and there is no algae, stains, etc.