Yeah, I don't see any chunks of plaster missing, just a lot of areas that look like they've been eaten away. I replaced what I think was about 15-20% of the water to bring the CYA and CH down, and shocked the pool tonight. Now if only I didn't have that pesky thing known as "work" to go to tomorrow morning. Hopefully the FC will stay up til I get home tomorrow night, and I'll start on the brushing. Not looking forward to that part for sure. I'll pick up some baking soda on the way home too, as I'm sure the pH and TA will be low after the water swap.
In playing around with Pool Calc, it looks like if I keep pH around 7.8, TA around 90, CH around 350, and CYA around 70, then CSI should stay between 0 and .3, which will give me slower plaster deterioration but a slightly higher possibility of scaling, correct? If so, I like that thought process, as I'm not financially ready to refinish the pool just yet. I mean, heck, I'd like to get a season or two out of it since I just bought the place!
Thanks for everyone's help and advice so far!
Bryan