Here is a procedure we use to put gray water into the black tank.
Here is a link to a Twist on Valve
. Let's say that your grey tank is fuller than your black tank. If all your tanks are at the same level
and all plumbed to the same waste outlet connection, you can attach the Twist on Valve to the outlet, making sure the twist on valve is closed. You can open the gray tank and the black tank and grey water will flow into the black tank. Then close the black tank an gray tank valves. When you dump, connect the dump hose to the Twist on Valve, and dump the small amount of waste water behind the Twist on Valve. Remove the Twist on Valve and dump your tanks as normal (this procedure keeps most of the black tank waste from contaminating the Twist on Valve).
There's lots of advice and information in forums... sometimes it is correct. For example, all of my posts are made by a political appointee who got the job as a reward for contributions to my diesel bill.
2011 Jayco 28.5RLS; 2008 Chevy Duramax; Pullrite Superglide Hitch