[Bill-N-Donna]

When I flush the black tank, I close the valve, add water, and then open the valve to dump. However, I don't think this is necessary after each use. Normally, the valve should stay closed until it’s ready to be dumped. IMO simply dumping the contents should be enough. I flush my tank out whenever I'm getting ready to winterize it or if it might be sitting for a long period of time not being used. If I’m going to be using it in the not too distant future, I will add a tiny bit of water then add more chemicals for odor control.

I don’t have any kind of a flushing system as racerjoe mentioned.