My wife and I just purchased our first RV. It's a 2005 Dutchmen Class C and we are preparing to head out on a short trip, not too far from home, just so we can start learning how to use all the systems on this rig. The folks we bought the rig from were very kind and helpful and spent several hours going over all aspects of the RV, but after awhile you reach a point where it all seems to become overwhelming (I felt like my head was ready to explode!). I've been going through the owners manual and I'm finding that the more I read, the more questions I have. My first question has to do with emptying the holding tanks. I read Gary Brinick's (sp?) terrific article laying out how to dump the waste tanks. In it, Gary recommends not emptying the black water tank until it is at least half full, and my owner's manual suggests it be 3/4 full. My owners manual recommends putting enough water back into the black water tank to cover the bottom to prevent hardening of any residue that may remain in the tank. My question is, if my black water tank holds 37 gallons, how much water should I add back to the tank to cover the bottom? One Gallon? Two Gallons? Five Gallons? Thanks for the help, we definitely appreciate it!