Krazy Klean helps keep the toilet ring at bay. It does not completely keep them away, but they come back less often than without using them.
I've had this for a couple of weeks. I should have cleaned the toilet before I put it in the tank. Although, I will say that some of the water minerals are still on the bowl of the toilet. So far, the rest of the toilet looks great.
So far so good, haven't had it long enough yet to see if the hardwater will build up again, but it isn't causing any problems. Fingers crossed it will be improved. A few more weeks will let me know for sure.