Couple of questions for seconds grow CHEEZE

I was just wondering what the difference was between inline fans and duct fan/booster fans. They have the same CFM ratings on them, but what is the difference in blowing/suction. I was going to use either to exaust from a 400w cooled hood from a grow tent with a carbon filter. What cfm do I need to push the hot air out with carbon filter attatched? thanks guys

for a carbon filter i use 1300 cfm, for my ducting i use 400 cfm. Maybe that will help.

the cfm on ducting fans is on moving air. Alone as a fan ducting fans are pointess, unless you want 10 cfm or something useless. I use atleast 400 cfm to air cool 1200w of hps, and 200 cfm for exhaust the 3x3 tent. You will need inlines, not boosters. I keep the end open on my cooltube essentially having dual exhausts. The lines run to a huge scrubber above the tent. Pics in my journal. I keep a 3x3 in 72(night)-77(day) temp range with 1200 watts of hps thanks to vortex fans.

So inline is the way to go... If so, what would I need for a 4x4x7 tent with a 400w cooled hood connected to a carbon filter? And why does htg sell the booster fans saying they are for cooling hoods?