replying to homerlex, Don wrote:
Water softener are ion exchangers, not ion eliminators. They substitute
bivalent ions, calcium, magnesium, for monovalent ions, usually Sodium or
potassium depending upon the salt (chemical definition) used. It's actually
simple. Bivalent ions form non water soluble soap scum or precipitates with
soap. Monovalent ions do not. Soft water has the same amount of dissolved
solids as hard water. Sodium has simply been substituted for Ca and Mg. Total
dissolved solids are different, but still the same amount.

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