Last night as I was about to brush my teeth, the faucet made a k-chnk sound, and the cold water stopped coming out very much. Hot water still fine. This morning, the toilet is full of weird light-greenish-blue stuff, and little flecks of it come out of the shower. The other bathroom in the house seems ok. Any ideas what the hell is going on? Cyanobacteria? Oxidized copper? Does it have anything to do with the construction outside our front door mucking with pipes 'n' stuff? I am at a loss?