[fcatwo]

I think this is a situation where you have to take your chances and pull the inside handle before closing down. Otherwise it takes all day to dump. Also, it's customary to close the outside black water valve before opening the gray water. This flushes your hose and keeps any residual water from the black tank from getting into the gray tank.

The only time we open at an off-site dump is if it's the last dump before heading home. I also use good quality disposable rubber gloves when dumping - especially when I won't be able to wash my hands afterwards.