Product review (5 stars): Worked great for me
I have a Miele dishwasher that has a built in water-softening system and utilizes a salt reservoir to reactivate the water softener.

I operated it for years and years without any salt thinking that my water was soft already and didn't need softening.  Eventually (like after 7 years) I had an issue with the dishwasher building up deposits on the interior and the dishes didn't seem as clean as they once were.

I ran this descaler through the dishwasher, added some miele salt to the reservoir, adjusted the dishwasher to the actual water hardness in my area (see your manual) and it's like night and day.  The interior of the dishwasher sparkles like brand new.  I couldn't be more happy with this product.