Softening/Deironing
Softening means the removal of dissolved water in the alkaline earth cations Ca2+ and Mg2+, which can reduce the washing effect of detergents by the formation of calcium soaps, and lead to troublesome scale deposits in pipes and appliances. Colloquially from hard water soft water is produced. Softened water should not be confused with distilled or demineralized/deionized water water.
In case of deironing, as the name implies, the iron content of the water is reduced.