This setup works GREAT!!!
I leave my grey tank open but about once every month I close it a couple days before I dump the black tank so it has a chance to loosen anything on the bottom of the tank.
So lets say it's a black and grey flush day.
I open black and grey valves at the same time and turn on both valves on the "Y". I Have a clear 45 elbow at the RV's sewer connection then the sewer hose after that. I observe the water turn clear and close both tank valves leaving the water run for 6-8 minutes. SET THE TIMER ON YOUR PHONE !!!!!!!
Open both tank valves let run til clear, close and set timer, open til just the water is running thru clear from the hose. Now close the black valve. Let the water run for about one minute. Close both valves at "Y".
The black tank will easily go one week so I usually do the deed on Sundays.
The dropping the "BOBM" is not a bad idea I may do this also. MeAgain's method.
