I found the O Ring gasket gets weak and out of shape so when you replace the cartridge and screw the cap on it gets twisted out of shape and the canister leaks all over the place!!!! I had to buy a complete new unit as I thought I did something wrong? But I have two toilets and the second one just did the same thing. So you can only replace the cartridge once or twice if your lucky, then you have to buy a whole new one... too expensive!!!!!! Beware!!!! Other wise I would use it as I think it's great, if it didn't leak!!!! My wife loves it too!