Just a thought and you may have it covered, but if you did I missed it above. I know that UWE has stressed the ventalation for the tank, but can the odors from the combined tank make their way up into the trailer through the shower?
I certainly know that I would hate to open my door planning to relax only to find a very unpleasant odor hitting me in the face. That and swatting the flys away...........
Just adding my 2¢ worth
1975 31ft Sovereign International
........Rear Bath Double Bed Model
Tow Vehicle:1999 GMC Serria SLE Classic 1500 5.7Ltr
System: Jordon 2020 Ultima Brake Controller
Hook-Up: Equalizing Hitch and Sway Bar