I'm a newbie but maybe I can help. You say you have an exhaust fan and a carbon filter, right?
Maybe your filter is too old and not working properly or,
Maybe your closet isn't well sealed, or the fan to filter connection is leaking. Tent-type enclosures (especially home made) tend to not keep odors inside as well.
You need to install the filter fan in the room and exhaust it out, with no other way for air to get out.(except small air intake(s) ) Just placing the filter in the room might cut down a little, but then that clean air just goes by the plants and absorbs more odors...it's a viscious cycle.
Also, If you are not running the fan, like if it cycles or goes off at night, and the closet is opened and/or leaks when shut, then you now have an odor problem.
Trace these leaks and fix them, if you can't cut thru the current door, buy another unfinished, cut it, hang it, then re-install the old door when you're thru! I couldn't imagine growing in an apartment.....I'd be WAY too paranoid! :stoned: