The primary goal of water-softening ion exchange systems is to remove magnesium and calcium from waters.
Waters that contain carbonates of magnesium or calcium are said to be hard. Soft waters have very little or no magnesium or calcium.
Hard waters are economically and domestically undesirable because they form scales in pipes and do not form lather with soaps, among other effects.
Thus, removing the magnesium or calcium is a way of softening hard waters.
One of the ways of softening hard waters is ion-exchange systems.
More on hard water can be found here: https://brainly.com/question/2666625