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

At first I was disappointed, the cartridge stopped working after about a week. I've tried experimenting with this and found that turning the cartridge all the way upside down sometimes prevents water from entering the cartridge ports. The cartridge screwed in and I tried not to screw it all the way in and it worked again. You don't have to run it hard, but it seems to allow water to get back into the cartridge ports. It can actually be adjusted depending on how much blueness you want in the water, which will affect how long it lasts. I hooked up two of these in tandem, one with a bluing cartridge and the other with a chlorine cartridge. This way I get both a good cleaning and a bluing effect that we like. It looks like the manufacturer should state this in their installation and use instructions.