We always had a ring of magnesium in our toilet and it has done the job, finally something that works!
It usually only took 2 weeks after cleaning to see the hard water rings around the bowl. I cleaned and dropped krazy Klein in the tank and so far no more rings or stains! So glad I made the purchase. I will hold onto the pumice stone for a bit longer just in case.
I was skeptical at first, they would really perform as advertised and now I am sold on Krazy Klean Pro.
Much to my surprise this product actually works. I am giving them as Christmas gifts this year.
I purchased for our cabin because we have a lot of iron in the water and the toilets were always rusty. After 2 weeks the water is cleared up and not more brown rings in the toilets! I have purchased more for our other toilets.