Tuga and Karen,

Our 93 Country Coach has a 64 gallon black tank, 112 gallon grey tank and holds 134 gallon of fresh water.

Seperate manual dump valves for black and grey tanks.

I've never run our of "black tankage", but have filled the grey to the top. We frequently go five nights boon-docking with out a problem. I'm thinking about plumbing the grey to the black with a pump system to allow me to transfer some of the grey water to the black tank for capacity and to better clean the black tank.

Jon's right, they all seem to be different.

Mike K.