I don't have an answer to your question, but a related question. I've been using cal hypo this summer - for ease of use, to raise CH, and to avoid CYA. I've gone through two 25 lb pails so far and my CH has gone from 120 to 320 for 30K gal pool.

Now my question: I've seen numbers of 400 to 500 ppm thrown out as max CH, but also some threads where people have not seen any plaster damage with even higher CH. I would like to continue using cal hypo and I could see my CH getting up to about 500 by the time I have to close. I'll drain a lot at closing and I typically have to syphon off twice during the winter due to precipitation, so next year it will be down again, but is there a true max CH to shoot for assuming ph and alk are held in check? I want to avoid any deposits over the winter.

Plaster pool, obviously, no heater yet.