hey guys, so i have a little problem.. i have a 4ft tall 2.5x2.5ft grow box on the cieling there is a 5" duct inline booster (170cfm) connected to an elbow and then another inline booster (170cfm) and then connected to duct going out my window. thats the exhaust, for intake i have a 4" hole in a lower part of one of the wall. I am running a 150W HPS, and the walls are mylar'd. temps right now are 98F! i bought an elbow and angled/aimed it at the light on the inside connecting it to the booster on the ceiling, that gets the temps to 97.5F. tomorrow i'm going to buy a fan for the inside of it, and point it up to promote air circulation and hopefully get more air moving around and out of the box. i really don't know what to do... EDIT: i checked again with the elbow on, it said 98.4.... WTF
i guess i'll assume that by the lack of responses youre right about my intake. can i add a second hole for intake?
dude.. some times it takes days to get responses... not ten minutes yes the previous poster is correct... (ex. a four inch inline fan needs six inches more or less of passive intake) this does not happen every time... but you need a bare minimum of four inches passive for four inch inline... six is better in this case you have a five inch fan... your gonna need a minimum of five inches passive... maybe up to 7.5 inches... so figure out how to light trap it... and i get some cooler air piped to your grow
Go up to a 6 inch exhaust and get yourself a real fan. Vortex 6 inch 449 CFM High Power Inline Fan - Plantlighting Hydroponics Stick a speed control on it to dial it down.
encase your light in a cool tube, you'll feel the heat being sucked out when you touch the venting, not a dragonslayer but will take it down a few degrees and bigger intake keep it passive of course
Those booster fans are just that: boosters. They are not intended to be run by themselves, only to boost airflow where the air has to travel a long way through a vent. Get a vortex, or even some really high performance PC fans will do better than those fans. Also, as everyone else said, make your intake bigger.