I am using 1 carbon filter and fan to take care of the odor of my two 3x3 spaces and using 1 carbon filter and fan in the bedroom when I hang dry. Or if I just want to smoke in there it's useful as well.
Everyone that comes over says they can't smell anything growing until they come into my apt. Apts are required too give 24hrs before entering. Plan to be home and have something really fragrant cooking if they do enter. I also have a private landlord who never comes into my unit so I don't worry so much