If you get a 6" fan instead of a 4" fan, then you will likely need two Doran louvres to provide ample airflow. If you calculate the measurements, one louvre seems like it would be enough (64 square inches is more than twice the area of a 6" circular exhaust). But because of the design of darkroom louvres they do impede airflow somewhat with internal baffles, probably by around 50 percent. For this reason I had to use two louvres to get enough airflow.

And no prob, glad to help!
jamstigator Reviewed by jamstigator on . Filter, Light, Fan Setup http://img163.imageshack.us/img163/5443/inline1ti.gif I was wondering if the setup in the picture (but with one light) would be viable with the following equipment: 4-inch Carbonaire filter, 400W HPS Cool Tube, EcoPlus 4-in 170 cfm centrifugal fan. The cabinet I plan to grow in is about 3x3x6. Any input is appreciated, thanks. :smokin: Rating: 5