I'm wondering if I can get some debunking help.
Our water-testing system here typically calls for the addition of outrageous amounts of calcium to pools when given a strip water sample. It's a glorified scanner with a color-picker in it where different shades on the strips correspond to ppm's.
Being that 99.9% of our customers have vinyl liners (that's what we install), I never recommend the addition of calcium. Why buy stuff you don't need, and then have to drain water because the system told you to add 19 pounds of calcium?
However, I was told that "The amount of calcium in the water determines how much chemicals the pool can hold successfully."
Total BS? I'm not sure how calcium could affect the capacity of water to hold chemicals. Smells like an attempt to sell unnecessary chemicals to me.