Well I learned that our black tank valve doesn't hold THE HARD WAY !!!! I opened up the cap to attach the hose and I had a surprise waiting for me , after gagging for 10 minutes I put the hose on and flushed the tank,I picked up a spin on valve and installed it to prevent future messes until I could get it in for the warranty repair list I've been making,so we took it to lake murry in ok this weekend and I went to hook the sewer hose and found the sewer pipe coming out of the belly of the trailer loose and moving around, by the next morning the trailer smelled like sewer , the black tank had been seeping in the belly of the trailer. Somehow the pipe that exits the bottom of the trailer has come loose from the piping. I took it in today for the warranty repairs. Next time I'll put fresh water in the black tank to check valves before I use it