Recommended Calcium Hardness (CH) with Heater


Feb 19, 2021
Rockwall, TX
Newish pool owner here, recently went through my first SLAM (clorine dropped due to SWG issue and I didn't catch it). I had been a bit lax in testing and things got away from me. I'm now being more diligent about testing, possibly bordering on OCD behavior. (I live in North Texas and up until last week we hadn't had rain in about 70 days. We finally had a pretty good downpour and I found myself wishing it hadn't rained because I didn't want my pool water impacted. Mental note to tone it down a bit.)

Anyway, I had been diving deeper into calcium hardness info and I ran into the following TFP article: Calcium Hardness - Further Reading. One of the suggestions in the article was for folks with heaters (not that I need it this time of year -- ha), to keep CH toward the lower end of the recommendation, around 200pm, in an effort to minimize scale. This number didn't seem right given that Pool Math says the low end of the range is 250 and the ideal starts around 350. At first I thought the article might just be out of date as I found this TFP thread that talked about the recommendation for CH being increased back in September of 2015. However, the Calcium Hardness article was written in 2019 with some updates (including heater info) in 2020. I also ran across this post from JamesW that suggested preventing scale by maintaining a slightly negative CSI, limiting heater GPM, and cooling down the heater after use.

All that having been said, should I be making CH or other adjustments since I have a heater? Also if the suggestion for heaters is something other than targeting the 200ppm I recommend adjusting the article referenced above.

FC 4.0
CC 0.0
PH 7.7
TA 70
CH 255
CYA 58 (I'm creeping this up)
SALT 3000
CSI -0.21
Thread Status
Hello , This is an inactive thread. Any new postings here are unlikely to be seen or responded to by other members. You will get much more visibility by Starting A New Thread