Hi, I was looking at your problem, maybe a little late? But here's my solution/observation for this set up. Cooltube light reflectors are meant to isolate the light bulb from the grow room/area. In that way they prevent the heat from the bulb to rise temps in the grow room. To isolate the bulb from the room you should have ducting at both ends of the cooltube . One for intake of cold air and one for exhausting the hot air out. So your cooling the bulb and removing heat at the same time. To do it more efficiently you should connect a 4" or 6 " inline duct fan (worth around 30$ to 45$ at home depot or online at most hydroponics store with or without the 6" power cord)to the exhaust to force the airflow through the system. Basically it's pulling the fresh air in from the intake by the exhaust not pushing it through the ducts like some people do. And that way no smell can escape from the grow room by the cooltube. Never connect the inline fan to the intake it makes it woked harder for nothing and build up heat from the motor is transfered to the ducting system it's supposed to cool down. Hope this helps you or anyone else looking at this thread. And keep on growing!!