I run a 6" HO CanFan that blows in the mid-200cfm range. It is adequate to ventilate a 6x6x6 space that is naturally cool but contains 2k total of HPS. Your individual needs may vary, but you can't skimp of a fan if you are going to run a carbon filter and that would be an excellent choice. For a filter, I'm running an odorsok, and have smell still. You will probably want something a little burlier in an apartment.