Okay
I didn't seem to stir up the kind of response to my Microphor problem that I would have hoped for, soooooo.......
I HAVE THE FIX!!!
I will install a macerated toilet. I will have to cover the existing hole in the black tank. Then I would tee into the existing vent line behind the toilet, in the cabinet.
I looked at Thetford site, and they have a few to choose from. Does ANYONE have any recommendations for a well made unit??
I won't make the change until we are back in the states.
Thanks