[C320-list] Accessing holding tank vent

[Dave Hupe]

 Ed-
During my extensive upgrade of waste tank hosing, etc., I found the same situation as you.  The vent hose was tight on top of the tank, but very loose on the thruhull vent hose barb because the fitting is a smaller diameter (3/4" at the tank, versus 1/2" thruhull).  I too believe this situation (loose hose and venting into the space behind my medicine cabinet)  was a large reason for my odor problems. 
Instead of replacing the vent itself, I placed a reducer in the hose and smaller hose to be able to connect tight to the thruhull.  My odor problems seem resolved. 
Dave Hupe
1994 Cat 320 (hull #32)
Holland, MI