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
Pool Size
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
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.