...at least that was the pool stores reasoning for instructing me to add some calcium to my vinyl lined AG pool.
I took a sample today to get it tested to make sure my test kit was ok & that I was coming up with the righ numbers. Calcium was a little low & they wanted me to buy 10 pounds of calcium to bring it up. I told her if she could tell me what the calcium would do to help my pool I MAY buy some. She says, "The calcium keeps the liner from drying out." I asked her "Above or below the water line" but could not wait for an answer before laughing out loud in her face. The manager then got involved in arguing with me about it.
WAHT A JOKE!