So I just converted a garage into a room and got a 4x8x6 grow tent and I have noticed I have had a few problems. I tried reading through a lot of posts but I can't quite figure out what needs to happen next.


1st the setup:
-4x8x6 grow tent with reflective lining
-2 1000W HPS lamps in one cooltube both cooled by a single 6" 440cfm blower into the attic
-the ballasts are in the same room as the tent
-the room is 10x10x8
-my intake ATM (airflow from outside) is 3" ducting to a 4" 144cfm blower to 6" ducting to inside the tent.
the house has an attic and 2 vents to the outside, one in the attic one next to the tent.

2nd The issues:

-temp is steady at about 84 F with the tent open and 2 room fans blowing into the tent. The whole room gets pretty hot too which pretty much kills the idea of intake from the room itself. If i seal the tent the way its setup now the temp rises significantly (90+)and the tent poofs up (im assuming due to lack of exhaust). I think i need some advice on lowering the temp.

-The ins and outs:
How much ins and outs should I install? recommended cfm? do I need 1 fan for in and a seperate for out or can I seal the tent and use one blower as a sucker to suck into/ out of the tent?

In the future:
what is the best way to go about adding co2 later with a tent setup? im worried that if I set up co2 the exhaust will just suck it all out. but if I turn the exhaust off the tent will heat up and the smell will get out.

Any help pointing me in the right direction would be extremely helpful. i can answer questions or add pics of the setup if needed.

Well for the temp you might be able to fit a small A/C unit inside the tent or just outside and vent the cool air duct to your tent. As far as the exhaust fan, your dimensions for the tent are 4x8x6 so that looks like about 192 cubic feet, I would think you would be fine with a single exhaust port as long as it moves at least 192+ cfm.

Just found this on another thread so I thought I might help ya a bit also.

http://www.drugs-forum.com/growfaq/1635.htm

I think an AC will do it. Also an good inline exhaust fan that will pull the cold air through the passive vents in tent and also create enough negative pressure so the walls on tent are being pulled in and not poofing out.

I have a 4.5x4.5x7.5 tent and I have an AC outside the tent. I'm using a 600 watt bulb in a air cooled hood. My exhaust fan is about 340 cfm. The tent is in one of my bedrooms which is upstairs and my house does have central air but I got a portable AC just for that room so I didn't have to crank the temp down so much on the central air and freeze the whole house.

Anyways, with about 340 cfm I have a lot of negative pressure and with the ac blowing right next to it, it pulls the cold air through the passive vents. Tent is stable at 73-75 degrees. Your tent is bigger than mine but with the right fan and AC your temp should come down a lot. Oh, and I also did try to see what my temps would be without the AC on at all. With the central air and portable ac in room off the temps went up to around 94 degrees. Just having the exhaust fan cooling the light was not enough. The AC made all the difference.

Also you should try turning the intake fan off and see how much negative pressure there is without it. The intake fan is what's causing it to poof up. If you have negative pressure with it off then that 440 cfm fan may be enough. You don't really need the intake fan cause the exhaust fan should be pulling in cold air through the passive vents. I only use a little fan as an intake and it's a little bigger than a pc fan. I just use it to help move a little air in. Infact I probably don't even need it.