There are lot of responses to your message, so maybe this duplicates something. I used a FloJet pump hooked up to the camper battery for about 3 years, with 2 of us living in it while my old house sold and my new house was built. We used it more or less full time (had to replace the pump once). I hooked up a clear 4" connector with a hose fitting on it. I hooked up the hose fitting to my "house" water, and used it to fill the black tank ("backwards") to loosen up everything. Then I closed the "fresh" water connection, and turned on the pump. It streamed all of the effluent down a 3/4" hose(s) for about 300 feet to a drain. Worked PERFECTLY. If the 4" line clogged, I turned off the pump, and turned on the fresh water to back flush it. Had to do that maybe twice, but when I was finished (maybe about 20 minutes), my black tank was REALLY cleaned out. Highly recommend it if you want to avoid manhandling a 4" accordian hose, and us a much smaller garden hose.