There are several products that can be purchased at the grocery store that will de-mineralize your dishwasher.
Hard water causes mineral build-up in dishwashers. A mineral build-up problem can be identified by a few symptoms.
Look for: glasses that have a frosted or cloudy residue. This residue can’t be wiped off. The same residue will make flatware appear dull and plates to look dirty. The interior of the dishwasher will have a chalky build up around all the sprayer holes. The dishwasher won’t clean as efficiently.To remove the build up, remove all dishes from the dishwasher.
Take a full container of Tang, or other comparable instant orange breakfast drink and sprinkle the entire contents all over the interior of the dishwasher. Run the dishwasher a full cycle. The ingredients in the Tang combined with the hot water form a mild abrasive that loosens the mineral deposits that are clogging up the machine. Once this is done, the dishwasher will look brand new.
Turn the dishwasher on, and let the reservoir fill at the bottom of the machine. Add ½ cup of CLR to the reservoir water. Close the dishwasher and run another complete cycle. The dishwasher is now completely de-limed and ready to wash dishes again. This process can be repeated every couple of months to keep the dishwasher working correctly.
If the dishes are still coming out of the dishwasher looking chalky, then run them through a cycle with ½ cup of CLR. Run another complete cycle to completely rinse the toxic chemical off of the dishes.