Peggy, One more time...what is the recommended size for the vent line from the holding tank. I promise I'll print it this time and preclude my Oldtimer's Disease from causing me to forget what you've already told me...many times. Also, how about a source for a vent to which I will connect the new vent line at the hull. I looked in the WM and BoatUS catalogs and don't see anything appropriate. Thanks, Tom Ehmke