The spotting you see may actually be an etching of the glass. The cause for this etching is excess phosphate substances found in many dishwashing detergents. These phosphates are added to soaps and detergents as a chemical water softener. In already softened water, the extra softening causes a problem. To protect your china and glassware, reduce the amount of soap used, and since heat plays a big part in this problem as well, use the “energy saver” feature or no heat air dry to combat etching.
