Tom:

Thanks for the explanation. That's the answer that I was looking for; with 88gals of grey water and 61 gallons of black water - there is no way to overflow starting out with 120 gallons of fresh water.

I may be the captain, but I am an absentee captain! My kids use the coach with their buddies, and Karen & I stay home and let them tailgate.

Lew:

The grey water by-pass valve is used on a coach with one waste tank when you are dry camping out in an open grassland (Auburn University RV parking lot). There is a manifold that allows you to let the gray water drain on the ground as it is being used. The manifold re-routes the grey water away from the tank and thru the sewer hose hook-up connection.

If you attend POG III, I show you on my coach. It's easier to show you than it is to explain it. Maybe Jon or someone else can explain it better than I have.

Thanks for the response.