Holding tank woes
[John2000] You might try raising or lowering the front of the RV depending on which side of the outlet the tank is on, i.e., if the tank is to the rear of the valve, lower the front of RV. Likewise you might want to be sure the side opposite the valves is a tad higher than the valve side of the RV. Of course I don't believe the tank needs to be completely dry. Just close the valves and drain the hose by disconnecting and raising the end away from the dump. Hope that helps.