Use gray to flush black

BarneyS wrote:

Vintage465 wrote:
Before I got a trailer with a Sani-flush, I would drain the black tank first...leave the black tank valve open....Then......Carefully remove the end of the hose from the dump station hole and hold the hose up in the air, higher then the tank and reach down and open the grey valve. The grey water would run into the black tank 'til it equalized...tricky part was shutting both valves while you continue to hold the hose up. And there would be a little "mixed" waste water in the hose while you got it back to the dump station hole. I suppose you could install a third valve to manage that though.

Just get a Valterra Twist On Gate Valve and put it on the end of the drain pipe just in front of the slinky. That way, you can close the valve, open both grey and black valves, and the liquid will equalize without going down the slinky. When done, close one of the tank valves, open the Valterra and drain as usual.

It looks similar to this one but without the clear plastic elbow.
Barney

I like the method that Vintage465 uses. I do the same except I can twist my outlet manifold upward to stop the flow through the hose. Just a quick way to do a little extra wash of the black tank. The more gray water you have the better it works.