[DmaxDually]

I use the flush king valve. I dump the tank then fill an flush until the water is clear and solids are gone. Usually 2 or 3 flushes will do. I keep my camper in a storage unit so like to have the tank empty and as clean as possible before I put it away. I also will fill my black tank a little before I use it for the first time after I dump it to try and keep the solids from sticking to the bottom of an empty tank.