Cooling issues(grow hut)

I have a small, 4X5X2 size grow hut, divided to make two chambers, a flowering (2/3 of the tent) and a veg(1/3). My question is how can i keep the temp down to atleast under 80F with two 150w HPS in the flow. I have a 12" cirulation fan but i need exhaust. With both hps lights on the chamber reaches almost 110F! i need to find a way to exhaust air and keep the temp down inside the flow chamber. The veg does just fine and stays about 78F because im only rockin' 2 X 75 CFL's.
I have a 6" and 4" pre-installed vent housing in the roof and side wall of the hut. Can i get away with a 4" inline duct fan, or do i need to upgrade and get a 170cfm duct fan, or something equiv.?

I have been told by many that all you will need is a fan that can move the total volume of the chamber atleast once in 5 minutes, if this is tru than i could use a 4" inline fan to work because it has a cfm of 80? will this work? any help would be great.

LOL well there is no way around this you must get air cooled hoods and cool the lights. you must, no option. i have a 2x4x5 for veg with a 400hps and trust me you need air cooled.

I would def suggest putting in a 4" fan ASAP for exhaust!! I use a 4" inline duct fan with a 7 lb. carbon filter in my flowering but it's quite a bit bigger and it keeps my temps perfect.

Something to keep in mind is that when your temps exceed around 85-90F your plants will stop growing for a few days. Temperatures this high throw off the chemicals and environment within the plant and they just hate it.

Also if you can put your intake fans at the floor and your exhaust near the top since hot air rises. Good luck!