yea... i use a 3sq.ft x 4ft tall box and just a few computer case fans do me good enough... but then again i only use a 150w

intake near the botttom, exhaust out the top.. .fresh air is more important than circulating air... you can circulate all the stagnant air you want, but if theres no co2, the plant dies... fresh air intake is quite enough to provide sufficient co2 in a small garden