Headroom is not really a prob with cooltubes but you would most likely want to run 2 seperate fans, 1 for exhaust and 1 for cooltube and yes the 6" to 4" works cause thats what I run in 2 seperate cabinets.
tinytoon Reviewed by tinytoon on . HID Lighting (Cool Tube) - A quick question Alright, I'd love to move from CFL to HID lighting. The only problem that's holding me back is the heat. I know HID lights put off some mad heat, but that's just from reading. I'm looking for someone with experience to give me some guidance. I've looked at some 400W MH/HPS (Switchable) Cool Tube setups, but they all have 6" fan hookups. Could I get away with a 6" to 4" adapter running to my 4" exaust fan? Or is the heat too much for my fan to move? (a pretty high CFM fan, sorry I can't Rating: 5