This is my first grow, and I just switched from CFLs to a semi-air cooled 150W HPS from HTG supply. I bought their $20 80CFM duct fan for the fixture, and it's doing a good job of removing the heat, but it started making too much noise today. I fiddled with it but can't get it to stop. It makes less noise when it's horizontal, but I need it to be vertical. I can hear the noise outside the cab, so it's not stealthy anymore. Lots of people recommend the S&P TD series, and I was going to get the TD100 or the TD100x, but I noticed in their specs that the max operating temperature is 104F. The heat coming off the lamp feels like it's at least 100, so maybe the TD is not the best choice? Right now I want to put the fan directly on the light, but for my next grow I'll probably re-do the exhaust so that I'm exhausting just the light, with a carbon filter on the outlet, for stealth. So, ideally the fan I get should be able to push (not pull) air through a carbon filter. But I could get a tide-me-over fan just to finish this grow. (I'm at about 40 days into flowering, and not sure how long it will go.) Attached are partial pics of my current set-up. On the ceiling there is a colander lined with carbon, and above that (outside the cabinet) 2 PC fans for exhaust. My cab is 14.5" x 14.5" x 60" high I'm also including a pic of the S&P spec chart, which comes from this site: http://www.solerpalau-usa.com/brochures/Residential_Light_Comm/TD_Extended_Brochure.pdf I can't re-attach photos I used in another thread, so here are links: http://forum.grasscity.com/attachme...28d1273134037-ok-hang-hps-light-angle-cab.jpg http://forum.grasscity.com/attachme...4281-ok-hang-hps-light-angle-ceiling_fans.jpg Thanks! I've got to post and run -- I'll be back later this afternoon, or this evening.