Need to add calcium

[haze_1956]

I was doing work for an ex-neighbor today. First time I had been to their house in a couple years.

Last year they had a gunite pool installed and he was complaining the plaster was geting rough and mottled looking. He had gotten the Pool Company, 20 minute tutorial and a package of test strips.

I went home and got my test kit,
Cl 3
ph 7.2
Alk 100
Cya 90
Hardness 0 !!!!

I know he needs to add calcium chloride. But not sure best source, I seem to recall "Ice Melt" was acceptable. Just want to verify or get recommendation for alternate or preferrable source.

Thanks