Calcium Hardness Questions


New member
Dec 12, 2020
Bryan, TX
Pool Size
Liquid Chlorine
Moved from here.. Calcium Hardness

I was excited to see someone else ask this. I also have considered asking this and want to add a question... what about the overall saturation index in deciding those limits for Calcium Hardness? We filled a new Plaster/pebble pool in December with really high initial TA, low CH, but maintained acceptable saturation index between -.3 and +.5. My CH is now at 230 due to soft fill water (autofiller) But I am hesitant to increase CH because my saturation index is still good. I anticipate as the temp warms up in summer I will need to address it though. Thanks!
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Texas Splash

Mod Squad
TFP Expert
LifeTime Supporter
Jun 22, 2014
Texas, San Antonio/Marion, South-Central Area
Pool Size
Salt Water Generator
SWG Type
CircuPool RJ-45 Plus
Welcome to TFP! :wave: In many cases, as long as the levels are within TFP recommendations all is good. But sometimes we have to manipulate something like TA or pH to make-up for one factor - in this case the low CH. Your CH will probably increase over the season, so as long as you compensate with the TA and pH the CSI will be fine. Note that as the water temp increases, so will the CSI. Stick close to the PoolMath APP and you should do well.

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