We recently got a new Bosch 800 Series DW. A water quality test strip comes with it, and there is a receptacle in which you can put the correct amount of special water softening salt. The test strip helps indicate how much of the salt to program the DW to dispense during a wash cycle, and is entirely different from the Jet Dry rinse aid.

Have you ever run the LemiShine thru your current DW, on a full cycle and empty of dishes? LemiShine is pure citric acid and does a good job of dissolving hard water deposits. I learned about it here at GardenWeb and now use it to clean up the water dispenser area on our refrigerator, and the water faucet spouts in our bathrooms.

Dishwashers with macerators typically also have filter screens, so they're pretty much all vulnerable to mineral deposits to the same degree.