The plaster went on my new pool 9 days ago, and the startup guy did great. However, I haven't seen him in 5 days. Did a sanity check of chemical levels, chlorine is gone (no surprise), but the pH as at least 8.2. I just put in some muratic acid to start pushing it back down while I figure out what is going on with the contractor.

What is the pH level where scale starts forming? The salt system is off and no salt is in the pool, what would drive the pH up like that?

Thanks from a newbie!