Keeping the room cool with your tent in will help to keep temps lower. Heat stress begins with leaves curling up from the outer edges making a canoe look to the leaves. Where are you testing the temps?if your temp sensor is in direct light from the bulb then it could be getting radiant heat causing a false reading. Take your temps in 2 places. The side wall of your tent, this will give you the ambient temp in the tent. And also just under the canopy out of direct light. Also placing your ballast as far away from the tent as you can will help to stop warm air being drawn in. I hope your ballast is not inside the tent as this is adding extra heat you could do without. J