check out my latest grow, the link is in my sig. Theres two grows in the journal though - my 1st ever grow, done with a cardboard box and CFLs, and then my 2nd and current grow, done with a 600w MH/HPS Cooltube system in a 2x4x5 tent. Everything works really well, and the Cooltube and fan works so well that i actually ended up upgrading to a 1000w ballast and bulb, not having to upgrade my 480cfm blower that i was running through the tube. other than the seeds i bought, the cooltube was the best investment of the entire grow. i recommend getting one to anybody who is interested.
My only regret however was not picking up the 24" cooltube, as opposed to the 19" tube that i bought. I couldnt find the premium cooltube when i was looking for it at the time, and i think it would have worked much better for me. For my next grow i think ill be picking up one or two Dual Cooltubes so i can run two lights out of the same reflector, while only needing one blower per tube. Anyway, sorry if im jacking your thread with my babble. The Tube rocks man, i wouldnt trade it for the world
--one more thing though, about your most recent question, YES, you would definitely need to get something stronger than a pc fan if you wanted to run a Carbon filter and cool off your lighting system with the same fan. In my case i have the Carbon filter hooked up, and then ducting running to the other side of my tent, followed by the Blower, which is sucking air out of the filter, and then blowing the air through more ducting, through the cooltube, and then out the exhaust. The air exchange rate is pretty good, and if your going to be running the scrubber and the light with the same fan, your going to want to have a high air exchange rate to keep the stale air out of the room.