I have a Niagara "tipping bucket" toilet that I actually like, really reliable - however, it started flushing poorly, and I read about taping the underrim holes with duct tape, dumping CLR into the tank, letting it sit overnight, then carefully (using a dental mirror) chip away at the crud blocking the rim jets. Got a lot of junk out - also, on the siphon hole across from the drain, I got a tubular wall of scale out - improving flushing performance greatly. In my kitchen, I have a 4 gallon mini-tank water heater that supplements the central hot water, and every six months I have to take it apart and clean out the crud and replace the anode rod - I finally installed a Kleenwater hot water filter for scale - I had already installed a Clearwave water conditioner, which I have been told is not enough for our hard water in San Diego county, which is about a 4 out of 5. Should anything be installed on the water line to the toilet? I installed a clearwave near my bathroom sink, as the faucet there seems to get damaged by hard water after a few years. I also get black specks out of the rim jets, I have been told that is mold? I have been told I could stick a product called Magnaloo or similar, to the inside of the tipping bucket - affixing it to it - to reduce the scale.