hey joesmoe,maybe in the place were the light is you should just one pc fan to just vent out the heat and just do a passive air on the other side to bring in cool air.And you dont really need a squireal cage just a pc fan that pulls 70 cfm and just place some replacement carbon filter over it.That carbon filter is like the exact thing as a filter, you can buy at home depot for 21$.Just cut out a piece and place it over the pc fan and the air being sucked through is clean,and you can use some bounce dryer sheets for a good clean scent.