High calcium, high alkalinity, old plaster

I have a nine year old, 30,000, in ground, gunite pool with SWG. My calcium and alkalinity have been climbing slowly for years. Last year it was 400 and 110 respectively. This year it has jumped to 525 and 130.

Other stats: temp 86, FC 4.5, CC 0, pH 7.2, NaCl 3400 (target 3500). 2-speed pool pump runs on low speed 24/7 with SWG on 25% of the time.

1. Does plaster contain calcium and might its deterioration release calcium?

2. I've read posts about lowering calcium that talk about "vacuuming to waste". My vacuum goes directly to the filter. Is there any trick to setting things up so that it vacuums to waste?

3. I see lots of posts about replastering but haven't seen any that say how you can tell when it's time to replaster. Any suggestions?

Thanks,

Steve