Calcium Hardness, vinyl liner, saturation index, gas heater


Well-known member
Jul 18, 2015
Zeeland MI
I see a lot of posts and recommendations on here that say CH levels do not matter in vinyl liner pools. I understand that it will not affect the liner itself. I am curious though about the effects of a low saturation index on pool heater exchangers and cement pool decks. Many other sites suggest that a saturation index below -.3 can be corrosive and cause pool deck pitting and metal corrosion. The holy grail Taylor water test kit even comes with a saturation index wheel. So why does everyone on here say not to worry about it?


Gold Supporter
TFP Guide
Jul 21, 2013
Northern NJ
Read Calcium Hardness - Further Reading

Pool heat exchangers are damaged by low pH or high saturation index causing scaling in the heat exchnager.

I can't defend the nonsense other sites say.

The saturation index predicts how the water chemistry can affect different areas of the pool - plaster, the heat exchanger, and inside the SWG.

You can read CSI and LSI - Further Reading

Vinyl pool with no heater or SWG then CSI is not a problem unless you let pH get real high and get scale on the vinyl.