I'm setting up a perpetual harvest garden with my veggie & flower chamber in separate cabinets. My veggie cab houses 4 42w cfl's with the following dimensions: 32 1/2" wide x 12" depth x 13" Height and i'm not sure what size in-line fan to use for ventilation as 4 of those bulbs in such a small space will most likely emit a large amount of heat but I don't want to go overkill and spend more than I should on the wrong fan. I'm currently looking at this 6" fan at htgsupply High Tech Garden Supply for $24.95 and the following 4" fan for $19.95 High Tech Garden Supply. Any suggestions are very much welcomed BTW for my flowering cab, i'm using a 250w HPS/MH conversion bulb with a homemade cooltube & 6" inline growbright 424 cfm for easy breezy growing