Product review (5 stars): The only thing that works!
I live in South Central Texas where we have VERY hard water. Most people have a water softener, but our house didn't come with one and we don't want to spend $1000 to have our house replumbed to install a water softener. I bought a brand new dishwasher, because I thought the old one wasn't cleaning very well. Still had dirty/spotty dishes. I tried a variety of DW detergents, rinse aids, etc. The hang-in-the-rack solid rinse aid came close, but not close enough. I had resorted to running the dishes through a rinse cycle with vinegar EVERY time I did dishes. Then I Googled "hard water spots on dishes" and found this filter. AMAZING! Works great! The dishes are actually shiny! It says to replace it every 6 months, so we'll see how long it lasts. When I buy a new one I will buy a few!