never have the fan blow straight down on a plant because it can cause wind burn. Think of the outside how the wind blows from the side and can gets more air under the leaves. they stress way to much when blowing down on the leaves. I would get put the fan on the floor and have it blowing up at the lights to keep it cool and the plants will still get good air but I would need to see you grow room setup. Also its ok for the top soil to be dry but put your finger in two inch's on the side of the pot if its moist its fine but not wet. try to have if dry as long as possible. plants to better in dry spells then over watering. if the humidity is low and hot temp then the top soil will dry in 2 days easliy. I water every four days in a 3 gallon pot with half gallon of water and hum is 50% and temp is 75 and I always have a fan blowing up at the lights and havent had any problems. hopefully that will help a little, good luck.:thumbsup: