Hi, I have a 20 year old house with copper piping. The house has had a working Culligan softener since new. I just verified the softener is working, generating zero GPG water per a Hach 5B test. I am on city water. I am having a growing problem on the hot side of my plumbing, with some slight reduction in flow. It seems I am growing some sort of yellow/white crud in the hot side stop valves, at the connection to the dishwasher and washing machine hoses, etc. I can even see this white/yellow stuff building up on the orifices inside my brass shower valves. The water heater is 2 years old. The dip tube is in perfect shape (just checked). I just removed the hot side stop valve under the master bath sink, as well as the stop valve under the kitchen sink, and found an unreasonable amount of this yellow, granular, corrosion-like looking stuff blocking the valve. In the MBR valve copper pipe where the valve attaches had this crap clogging the pipe about 1/4" deep. Seems to be leaching out of the metal. I soaked these valves in vinegar - they did not fizz. Left them overnight in vinegar, and the valves were pretty darn clean by morning. I have turned off my softener for now - fearing I am over-softening the water (if that is possible). Water heat temp is at 130F. City water has a hardness of 7 GPG. Any ideas??? Thank you all!