Sorry hudson.... my intake is at bottom left corner. Intake is 3" and exhaust is 4". By top and duct fan i mean the duct (picture) i will run during dark period because there are no light leaks thru it. The top (mounted directly on top of box) I havent bought yet. But its gon be a 85 cfm comp. cooling fan that i will run during light hours because it will leak light real bad. I will cover the top fan during dark hours to keep from hermies, and run duct fan during dark to keep temps ideal.

I will post pics of the 85cfm and its mounting spot later this afternoon.

:jointsmile: