HERE YEE HEAT LESS ok ok ok. I see my experience with heat will help.
as stated several places on the internet, put your hood fans/coolers BEFORE
the bulb. this creates positive pressure, while pulling out causes negative pressure.
At first I didn't believe it. BUT since I put the inline duct fan before the bulb, I have had to turn off my top room outlet fan, and both my bottom I/p fans and still can't get the 4 x 4 indoor room past 73 deg f. also Huge heat drop with new hortilux 1000 hps. wow.
think my used bulb was worn out, infared, heater. growth was slow too. ok now.
seriously ductfan goes before the bulb. tell all about my experience. something to do with
positive pressure blowing all the heat in the hood out. neg pressure causes hot hood air to
stagnate in the low pressure corners. its true. pos pressure causes all hot air out. This didnt seem right to me at first, but its an important amazing fact of hood cooling. pass the knowledge.
on my 1000hps hood I/p I put a 460 cfm centrifugal fan, (was too loud, but a cheap speed controller for $29 enabled variable speed, its set to minimum speed. I cant hear it).
now if we are not discussing cooling hoods, therefore rooms, then neg fan helps vent top air of course. I'll never have heat fears again. I now know the secret.
pos fan prior to bulb/input hood duct. in other words, its better to blow into a warm hood, than
pulling it out. the warm air heats up the hood/room too much. VITAL HOOD COOL FACTS.