Always pull the air, never push it.
+1
Your exhaust fan always needs to be bigger than your intake fan. If the tent is in your home such as basement or something, just duct the heat out through a pipe past a charcoal filter then outdoors. You dont even need an intake fan, static pressure will pull cold air in. But yes, have the air intakes be at the BOTTOM of the tent - hot air rises.
Also, you can use increased humidity to help manage temperatures. The moisture helps absorb the heat. The smaller the droplets the better - you want it to flash evaporate because that takes a lot of heat with it.
This concept is a bit counter intuitive to people because for people, hot temperatures + humidity = increased perceived temperature. This is not actually the case though, but it occurs because sweat is our cooling mechanism and it works by evaporating the moisture off our skin, taking the heat with it. In humid environments, its harder for the sweat to evaporate, so we feel hotter. Actually, we are hotter, because the sweat isnt cooling as effectively.
Though you may not need an intake fan, having a simple $20 walmart box fan at the bottom circulating air is a good idea to prevent hotspots from developing. I used a desk fan that would move back and forth, helped a lot.
Also, Sativas can take a lot of heat before having problems. Up to 85 would be okay, any higher and you are risking problems. Some sativas thrive at 90 but those are few and far between.
Good luck! Heat is the biggest problem growers face here in AZ!
