get that fan outside of the tent for starts. Make it suck instead of push like mentioned. This alone will help your problem tremendously. That fan has enough power to easily cool your whole tent/light. If that still isnt quite enough try using an ice box on your intake. I have alot shittier fans it was 90 degrees the other day, no Central air running cuz that day was a fluke for spring now its back to 60's and I managed to hold at 86 which some would say it to high but they love it. Just frightens me when I get to the 90 mark that is when I would seriously consider spending the big bucks for a good fan such as yours. Once you move that fan to the outide of your tent leave the other ducting in there tie it off high on that ceiling bracket in your tent that way you can keep your vaccum working. Then once fan is out put another piece of ducting back on and continue it to wherever you're exhausting. Also, with that ducting still inside tied up high you could attach a carbon filter then wa lah you have your tube exhaust,your vaccum, odor control and your peace of mind that it will stay cool and have no smell. IF you need added air flow hook up a cheap booster fan to either your intake or existing exhaust. But I wouldnt think you would need it as long as you can dump the air in a pretty short overall length of ducting.