I have a 6000ish gallon fiberglass pool. I chlorinate with 8% bleach and have done so for years. This year my alkalinity refuses to stay in the 100-110 rage that I try to keep it in and my PH always seems to move up to 8.0. I've never tracked CH but I just tested it and it is 40. Any suggestions? Water tastes somewhat salty. Should I just let the ALK drop down to where ever it wants to go? Any suggestions on what could be causing this?