In my basement there is a plastic basic next to the washer into which the dirty water from the washer flows. It also has two faucets...hot & cold. For years I've only used the cold water with my washer because the hot water faucet leaked some black gunk. I've tried flushing out my hot water heater to no effect. Also, I'm not seeing it anywhere else. I recently tested it to see if I could see it, and there was a very small amount. I filled a clean 3 gallon white bucket with hot water and afterwards could see a very small amount of black "stuff" floating on the surface. The amount, all together, was about the size of a quarter of a pea...very minimal. It was apparently light in weight as well, as it floated upon the water. If the hot water was clean I would like to use it to fill my Jacuzzi. I'm currently using a hose from outside, but this cool water takes a long time to heat, and my gas is my cheaper than the electricity that runs my Jacuzzi. However, I'm not sure if this can be fixed. I live in a house built in 1948. Do you have any idea what this "stuff" could be? Also, is there any way to fix it, clean my pipes or whatever, so the water runs perfectly clean? Thanks!