I've decided to wait on AA process until after pool drain/refill in a month or so. Ideally, my CYA 170, & CH 750 will both be at better levels then...fill water tested at 250 CH. I will test vitamin C on stains once FC comes down, however. I should probably look at heater condition, as well...fairly certain it is original 1997 (RayPak RP2100.) No algae issues since FC levels up.