To prevent etching on glasses in the dishwasher, make sure that the temperature of the water in the dishwasher doesn't exceed 140 degrees Fahrenheit. Do not use the temperature boost, power boost or power scrub water heating programs of the dishwasher. If the dishwasher has a no-heat energy saver dry cycle, use it for washing glasses and other glass dishes.
Don't rinse the dishes to wash off food remains before putting them in the dishwasher, as doing so makes the dishwasher detergent more alkaline. High alkaline concentration is one of the things that can cause etching on glasses. However, it is acceptable to wipe or scrape food remains off the dishes before loading the dishwasher. Rinsing additives can also help to prevent etching on glasses. Be sure to pour the recommended amount of the additive into the correct dishwasher receptacle.
If there isn't a receptacle for the rinsing additive in the dishwasher, obtain a special basket for the rinsing additive, and place it in the back on the lowest rack in the dishwasher. It can also help to find out the hardness of the water that the dishwasher uses and adjust the amount of detergent that you use for the dishes. For example, if the water hardness is about zero to three grains per gallon, use 1 tablespoon of detergent. However, if the hardness is about 10 to 12 grains per gallon, use 4 tablespoons.