New to pools. We moved into our new home with below ground pool approx 2 months ago. Size of pool is approx 12,000 gallons and has a small connected spa, both with concrete/plaster finish. Pool's is somewhat stained (former algae blooms?), but okay for now. Thought we would have to acid bath or re-plaster sometime next year. I found your website and I am following the BBB method now.
My problem is that small pieces of the plaster are coming off and exposing the concrete(?) underneath. Pieces vary from the size of a quarter for most spots to one spot that is 3inches by 2 inches. The exposed area beneath is rough and if I rub it with my finger it feels like loose particles of aggregate come off. This has been happening over the past 2 months and seems to be getting worse. My fear is that I'm doing something wrong chemically? Maybe it was a bad plaster job? Here are my latest test results:
Water quality looks very good/clear.
FC - 8
CC - 0
TC - 8
PH - 7.8 (using dry acid mixed with water in 5 gallon bucket instead of liquid MA)
T/A - 70
CH - 400+
CYA - 50 (this had been as high as 120, but drained 1/3 of pool water and stopped using the chlorine tablets)
Temp - 64