I have the same size tent, with a 600w non-cooled hood. You need more fans to make the air circulate...
I use 3x 10$ fans and my temp stay around 82-83. I have 1 fan by the air intake (the flap) pushing air up and 2 others fans are on the other side (mid height) pushing toward the plants and...
I have a similar tent setup, exept my 600w has no cooltube/coolhood, and my temps are around 27-28.
Air circulation is the key.. Post a picture of inside, i'd like to see how and where you put your filter and fans.
Good luck !!