If you are using PVC or any white piping, you ought to spray the bends black-- light reflects around relflective bends. As your piping is on the intake, there must be some sort of black, non-toxic solution you could put in there-- stay away from noxious spray paint for those bottom bends. Dryer ducting (that bends) reduces your throughput by a siginifigant extent using a stealth fan. You can buy black pvc. Look into it. Good luck, and it's good to see cfls proliferate. I ain't (I'm stealth too) got bucks for HPS and MH, much less ballast and etc. I found real 40w output cfls at Home Depot in the specialty light section. Three Kelvin values: 2200 (no thanks) 3700 for flower and 6500 veg. Combo for flower, actually. I dig your ingenuity. Peace, d