So I have been having some heat related issues lately, which is odd because it is winter but whatever. I always read "keep the plants as close to the light as possible! If you can put your hands on the top of the plant and it isn't hot it is fine!". So I usually kept the tops within 5-6 inches of a rather weak 250 watter all this time, not realizing just how incredibly hot (with very little humidity) it is near the lights. My hand can easily sit under the light at that distance without feeling much of anything. Good right? I did a test at varying distances just to see what the temp/humidity readings were, and this is with a 6 inch cool tube(that I feel is essentially useless after this experiment BTW) and fan blowing the hot air from the tube to a vent in the ceiling. The light is about 5 feet off the ground, it is a finished attic I am growing in. The center of the room temp (about 12x14 room) was a consistent 79 degrees, and the humidity was 34%. Directly under the light (not touching but within a couple inches, the temp was 113 degrees, and humidity was 11%! At 6 inches below, the temp was 92 only 25% humidity At 12 inches the temp was 89, humidity was 27% At 18 inches the temp was 85, humidity was 27% At 24 inches, the temp was 83, humidity was 27% As you can see very close to the light is just asking for the plants to fry, I mean that is crazy high and while some might survive others won't be able to handle it. I had no idea it would be even close to that number, and the humidity loss just makes it worse. I am really trying to dial my grow room in, I have been growing for a year with bag seeds (harvested over 200 plants in that time) just to get experience but now have some good strains going and don't want to mess them up. I can't even imagine what the temps would be like under a more powerful light, they have to be sky high compared to the 250 watter. Back to the cool tubes, they seem to be worthless. I have a 6 inch inline fan blowing the hot air out and it doesn't seem to make that much of a difference. Now here is the conundrum, if we are losing a huge amount of lumens the farther we go away from the light, where is the middle ground? What should the "room" temp be around if we are at roughly 10-15 degrees above that under the lights? Also should the "room" humidity be adjusted as well being we are losing moisture under the heat of the lamps? I have 2 500 watt T5's that I am going to do next to see what they come in at directly under, normally the tops of the veg plants are darn close to the bulbs in that room. Can't imagine it will be anything like the HPS but I want to see.