Thank you both for your responses.

I'm not opposed to draining and refilling, if that's the easiest way to fix both the CYA and Calcium issues. However, our daytime temps are already reaching 110 here in Phoenix. Isn't it a bad idea to drain my pool, even partially, with those temps? Or is that another myth perpetuated by the pool stores? If I do go that way, how far should I drain to 1) prevent destroying my pool, 2) bring the CYA and calcium levels back into manageable ranges?

If Pooldoc knows another way to fix this without draining, I am open to all options.

I can't thank you enough for all your help!