Low calcium and fiberglass pool


Jun 28, 2020
Tulsa Ok
First year with our pool and I’m still getting the hang of this chemical testing. From what I understand, since I have fiberglass, the fact that my calcium hardness is a little low is immaterial to me right? The pool math app keeps telling me to adjust it and add 50lbs of stuff and I figured that’s about $75. I was about to go get some then remembered reading it’s only important doe concrete....right. I know if too high it’s and issue. But not hard enough, not my issue. Main reason I’m asking is in case it interacts with other chemicals and is more likely to impact chlorine, or algae or ph or anything else. Or if it’s totally independent of other factors.

thanks for the help


Gold Supporter
TFP Guide
Jul 21, 2013
Northern NJ
Pool Size
Salt Water Generator
SWG Type
Pentair Intellichlor IC-60
Fiberglass pools need calcium. The main function of calcium in the water of a fiberglass pool is to reduce the chance of staining. Primarily Cobalt staining.

Calcium does not interact with other chemicals.