CH at 800


Bronze Supporter
Oct 7, 2019
San Martin, CA
Hello Trouble Free Pool. I have a question about the CH in my pool. I have just completed my first year of owning a pool and the help I have received here has been indispensable. Last December I did a drain and fill because of extremely high CYA. We are on a community well and the CH content is pretty high. I tested the well water this week and this is what I got.

FC - 0
PH - 7.3
TA - 340
CH - 360

Getting a handle on testing the CH took while. I could never get the test to turn blue. It just stayed purplish. Then I started doing the dilute test and that seemed to work. The most recent test of my pool water is this.
FC - 6.0
CC - 0
PH - 7.6
PA - 60
CH - 800

So the CH went from mid 300's to 800 in one years time. I have read that doing a drain and fill for high CH is a thing but I'm wondering if I can wait another year or should it be done this winter.


Gold Supporter
TFP Guide
Jul 21, 2013
Northern NJ
Pool Size
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
At 800 and above your CH starts making managing your CSI difficult. Waiting another year if your CH clims another 400 or so ppm can lead to scaling problems. Better to plan a drain at your convenience.

Read Managing High CH Levels

@mknauss has experience managing high CH.


Mod Squad
TFP Expert
Bronze Supporter
May 3, 2014
Laughlin, NV
A high CH is manageable. I do not see a SWCG in your signature so no issues with that. Regardless, you will get waterline scale. You can manage that with pumice stone and acid or hire a kieserite blasting service every couple years. Read about CSI and manage it using pH and TA management. It will take quite a bit of acid with your high TA fill water.

The issue you have is evaporation. Your CH doubled over the past year as you evaporated a complete pools worth of water over that time. As Pat stated, using softened water for autofill will help manage that tremendously. Do you have a whole house softener?


Bronze Supporter
Oct 7, 2019
San Martin, CA
Thanks AJ, Splash and mknauss for your responses. I knew managing the CH was gonna be a little bit of a pain and now I know what my alternatives are. The water softener idea might be something to aim for long term as a source for fill water. I also never thought of a cover as a evaporation preventer. For now I’ll have to look for the little pump I used last year. I know it’s around here somewhere.