I didn't know that my dishwasher needed salt until I bought my new Bosch dishwasher. The technician told me that my water was too hard, and he showed me on his meter and highly recommended that I buy dishwasher salt. Well, my dishes never looked better. Now, I'm wondering if my other dishwasher failed because I didn't use the salt with my hard water. I have a water filtration system, but the water was still too hard, so I highly recommend that if your dishwasher has a salt dispenser to test your water and use this if needed. My glasses sparkle like never before.