First some info on my pool. It's inground, pebbletech finish, salt water chlorinated, with attached spa. My latest numbers are:
FC - 5
CC - 0
Cya - 40
PH - 7.4-7.6
TA - 50
Cal - 300
Salt - 2900 ppm
Temp - 85
I've had this pool for about 4 years, I change the water every 2 years. For the...