Learning experience

[Racinforthefinish]

We just went on a two day camping trip to Raystown lake area in Pa. We decided to stay at the Susquehanna campground which is very primitive. We are self contained and have solar so no problem. On the second day I was using the outside shower cleaning up my grill and cookware when I started running out of water. I got to thinking and I knew this camper well enough I hadn't used 90 gallons of water and then came that Ah Hah! moment. I had put cut-offs on the vent tubes so all my water wouldn't siphon out going down the road. I opened the vents up and heard lots of gurgling for awhile, the pump came back on, water was flowing and all was well. What I learned was with the vents closed two days is the limit if I want to keep using water!

[dewey02]

I'm guessing your twin fresh water tanks were puckering like crazy.
Yes, you need to keep those after-market valves on your overflow/vent tubes open when you fill, and open when you draw water. Only have them closed during your travels.