Hey buddy..
i did a recording of my setup because alot of whats said can get a little confusing.. im a begginer grower and i had a problem like yours with heat too.. and i found a cheap resolution to fix it.
im running a cooltube with a 6' inline can fan. which is connected to ducting which leads out of the tent, out of the room which the tent sits in and into the roof.. thats the only way you can reduce the heat.
the trick is to allow the heat to escape the tent and out of the room which will drop temperatures.
and also make sure you have an inline fan which brings in cool air into the room also.
check out my video.. in total i spent $120 on my fan, cooltube and ducting along with the flange which the ducting is attached to in the ceiling.
p.s make sure you have a fan inside your tent oscilating also it helps bring temps down a few degrees.
enough said... i hope i have helped the mariujana growing community
[video=youtube;kqb5VIvDQHU]http://www.youtube.com/watch?v=kqb5VIvDQHU[/video]