Bests & Worsts Reviews from Amazon

I find it hard to believe myself, but it happened! A few weeks after I dropped this in the tank, I noticed some small black specs coming from the jets inside the bowl when the toilet flushed. Didn't think anything of it at the time. Time went on, the black specks got bigger and bigger. I finally popped the lid of the tank off, and it was loaded with black mold! I've never seen this happen before and using these tablets has been the only change made. I've since cleaned the tank, which was a real pain to do by the way, and will not be using these tabs again. So far, so good, no more mold.