Yes, the second one is the one you want. The purpose of running a vent thru the light is to reduce the heat the lamp produces, and your first example does not do that. its defeating the purpose, and will help very little in getting the temps down.

keylime
keylime Reviewed by keylime on . Cooltube exhaust = closet exhaust OR Cooltube exhaust + seperate intake and exhaust hello growers :smokin: i have a question: 250w hps/mh, 2.5 x 1.5 x 5.12 foot, fan/s any suggestions ? first layout is all the vantilation through the cooltube's ducting, with passive intake at the bottom, like this: the problem that could be here, is that the air that the fan is sucking is hot, because the intake is near to the light. or that is ok because the warm air inside the tube is quickly replaced with cool air ? Rating: 5