Tuga & Karen,
It's hard to get a straight answer from this bunch, I'm not even sure I can do it, but here goes...

My Marathon has 2 tanks, the grey is 88, the black is 61 and the fresh water around 120 if I remember. Mine are plain manual dump valves, just the way I like it, no motors or electric valves to go bad. The sewer hose hook up is also up in the plumbing bay with a removable panel below to hook up your hose, unlike the Liberty's that hang down and get knocked off.

When things get bad with your party animals, turn off the pump, tell them the tank is full and head for the fresh smelling porta poties. Then when your inside all alone, hit the pump laugh. Hey, your the Captain, remember....