You need to put your Anderson Valve in the tank position. I have my hose attached to the RV and add my clorox solution to the other end of the hose. I attach the hose to a water supply, turn the water on to the hose which will then begin to fill my tank. As soon as one of the overflow valves start dripping water from my fresh water tank, I turn the water supply off and let the water sit for awhile in the tank. I then turn my water pump on and run the tank water through all my faucets and then let that sit for awhile. Once completed I empty my fresh water tank with the drain valve. When the tank is empty I close the tank drain, fill with water again and then pump fresh water through all my lines again.