I keep an oscillating fan on and leave my temps around 78. I use a capital 4 air controller, turning my fans on when it gets above 79 degrees. Some of the tops of my plants get as close as 7 inches from the light and I have no issues. I leave the oscillating fan on 24/7 though. What are you feeding the plants? I suggest you look into an air controller, makes life easy. PS, here's my girls. The ones in the front were vegged under an hps so they're a Lil lanky. The two in the back were begged with an mh. I'm in 7 gallon pots using sunshine mix#4 which is soilless mix with fox farms nutrient lineup.