Review on Enhanced Fluidmaster 8100 Flush 'n Sparkle Automatic Toilet Bowl Cleaning System with Blue Cartridge by Brenda Willoughby

This product works very well and largely corresponds to the description. It can literally be installed in about a minute unless you are having trouble removing your existing hose to attach this. Due to the fact that the rim/lid of some toilet bowls mates, the lid may not fit as it did before installation. Neither affects the product itself. With each flush, the cleaning solution is released and the water in the bowl turns blue. While I doubt it will remove existing stains, I am confident that it will sanitize and prevent staining, so I would suggest giving the bowl a thorough cleaning prior to installation. I've been using them in two new toilets for about 6 weeks now and there are no stains. The amount of solution released (and therefore the depth of the blue tint in the water) depends on the time between flushes. So if you need to flush a second or third time in a row, the blue will be lighter each time. My guess is that this is because the solution contained in the cartridge needs to "leak" over time. It's not really a problem but I thought it would be worth 1 star less. I'm not sure how to fix this, so I just want to deduct half a star. All in all, I highly recommend this.