After 2+ years of no problems, in the Bahamas and the U.S., the head vent on
our sailboat has become a problem in the last year. We try to do the right
thing: Odorlos, regular pumpouts with fresh water, etc. We are thinking
about installing an inline filter for the vent, thinking about using
something called the Shock treatment, etc.

But, before we do those things, we are looking for other suggestions.

TIA