On one hot water faucet I get particulates out of it. This faucet might be first in line from water heater. I replaced the gas hot water heater a year ago. I also drain heater every year. The other sinks do not get the gunk. some of the gunk looks copper metalic and other is soft gunk. I do have a hotwater pump to circulate the hot water so the water is hot in a second or two at the faucet. My old water heater was full of stuff when I replaced. Our water is ? with PH average of 7.38 and Hardness of 97.2/5.7 grains. Could it be my pump is corroded? Is there such a filter for hot water lines? Thanks for help. Jbt