Hi James,
There are several possbilities that are relatively easy and inexpensive to fix.
- Check the holding tank vent on the starboard hull near the bow. This can become clogged and prevent much needed oxygen.
- Check the hoses from your toilet to the holding tank to make sure they are not old and leaking and that they are the correct type to prevent odor penetration.
- Add treatment to your toilet bowl to chemically treat odors in the tank. (I have found Raritan Engineering is a good soruce of information and supplies to address this issue).
Also wanted to let you know that there is a new forum dedicated to T-31 you can use for future posts. (Although the head odor queston is applicaable to all Tartan owners)
Best,
Zach