New grow, Need ventilation & temperature help, Please.

Alright well, I have a 2.5ft x 8ft x 7ft room, currently pushing 400w sun-system built-in ballast light, I have one fan hooked to my light pulling the hot air up & out through an exhaust outside, and I have a osculating fan lower, that basically just moves the air around, My problem is, I have no idea how to get new air in without cutting holes out for exhaust, maybe it will be okay just pulling the air up and out? I'm also worried about temperature, its around 81 degrees in there, which is kind of high I believe, but yeah, I'd appreciate a few tips, Thanks.

81 is ok. Its already is getting fresh air in there if you have an exhaust thru passive intake.

My temp is 84 and doing fine. Circulation fans can even out the "passive" air intake.

Long as you stay below 90-91 you should be ok. You do have fresh air coming in right?

i don't have a direct vent bringing in fresh air, however, there's a 2 inch gap under the door which i have oscillating fans next too, and I open the door once or twice when the light is on, hopefully the exhaust fan i make-shifted to the light pull enough fresh air into the room, up & outside, and the other fans should spread that around, I was kind of thinking of letting a slow leak of c02 go in there for a bit too.

Hello All, just starting to go into flower on my first grow. Wouldn't have got this far without the folks here. I have about the same size area as 'Herb' 250w MH HPS, 4 inch inline and filter, exhaust into the attic, Intake 4 inch duct from attic that I attached to the back of a reg. fan. 12 hr day temps reach 82 , 12-nite temps are reaching 64 w/ just the filter running. What is the best temp range for flowering? I remember trolling the board and found someone who said cooler temps encourage heavier resins. Do HPS run hotter?