Normally calcium is removed ...
Published by Juan José Mauricci
Normally calcium is removed by ion exchange resin (softener) but in this process Ca is exchaged by Na.
But in this case it is probably that the sodium concentration in softened water exceed the maximum recommended by drinking water standards. Therefore I think that it is better to use softened membranes. The possibility of the use of this type of membrane depends on the concentration of the other ions present in the raw water. Please send me a chemical analysis of the raw water to juanj@outlook.com.ar