calcium=20... vinyl pool... problem?

[leejp]

Is a low Cal a problem for a vinyl pool?

P234 results
FC 3 (but I just added a jug of bleach or 1.7 PPM)
CC 0
TC 3
PH 7.4
Alk 100
Cal 20!!!
Cya 40
Temp 80

I hadn't measured Calcium hardness in a while but I was quite surprised to find it that low. I had been battling iron stains and have added some heavy doses of iron/mineral sequestrant. Otherwise it's been BBB (Tri-Chlor earlier in the season until the Cya got to ~40).

The pool looks good. The water is clear and the iron stains are gone (for now).

[CarlD]

No.
You can pretty much ignore calcium with a vinyl pool unless it gets close to, or over 500ppm.

Calcium's main function in water is to keep the calcium in the walls of plaster, concrete and tile pools from dissolving out. Just like you cannot dissolve more sugar to already-saturated water, calcium will stay in the walls where it belongs.

Vinyl has no calcium to dissolve, therefore no need.