Yes they are pulling air threw the filter. I have them hooked up to a speed controller to try and not put to much stress on them.so are you the cougar pc fans to pull air through the carbon filter? Those are great fans btw, I use them all the time, just not sure they are going to hold up for long pulling/pushing air through that carbon filter...interesting to see though! Like the ingenuity!
Its is sad.....haha but you are right with the hps being cheaper. plus Htg actuall store is only 20 min from my house, its greati'm sad you went with only a 150w hps lol. but i'm sure it was cheaper. the cab i lookin good though
i'm ordering the 180w panel next paycheck. can't wait.
the hps is in an enclosed hood with 2 4" flanges. so it will have its own intake and exhaust. what i have now is just room ventilationi fear your exhaust being inadequate for that HPS. atleast the 150's don't get as hot. make sure you have a nice breeze over the plants