Whats up?

Is it possible to run an intake duct from upstairs or a cooler room?

Where are you venting your hoods? If you are venting them into the room that is your problem. If you vent your lights outside or into a different room then your temps should come way down.

Also im not sure because I dont use CO2 but from what ive read it enables the plants to tolerate heat better. Dont take that as gospel because Ive never used it but thats what ive read. Hopefully someone who uses CO2 can comment on that.