On Mon, 07 Dec 2009 09:37:30 -0800, Gordon wrote:

This filter supposedly stops odor so why not vent inside?

It will lead to problems sooner or later. Peggie is a big advocate
of freely venting the holding tank with lots of fresh air. At the
very least, the filter will impede that venting. At worst the filter
will become clogged sooner or later and cause the tank to pressurize.
Use your imagination on where that will lead.