I have a DR80 with 400 watt HPS and I'm totally having heat issues.

The light has an air cooled hood so for a while I used a cheap 250cfm 6" duct fan as an exhaust vent at the top of the tent. So I had the 250 CFM exhaust on top of the tent, attached with ducting to the air cooled hood of the 400w HPS, which pulled in air from inside the tent. I keep two of the bottom vents open to act as a passive intake. The best I could do was keep the temperature inside the tent 9 degrees higher than the temp outside the tent. Now that it's summertime that's not cuttin it, cus my temps inside the tent are getting up to 85, and the plants are showing stress.

When I would feel the exhaust air coming out it was definitely hot, so the fan was doing what it was supposed to do by venting the light, so I figured the light must just be pumping out a crapload of heat, so I went and bought a 6" inline fan (Vortex knock-off from HTGSupply) rated at 424 CFM. First of all let me say that it's virtually impossible to fit this size fan inside the tent, its huge and the DR80 is not that big at all. I actually bought the 6" fan/carbon filter combo, hoping to get that installed also, but I attempted to put it all in today and had nothing but problems. After three hours of trying every different setup I could I ended up not installing the carbon filter and simply placing the new fan on top of the exhaust vent at the top of the tent (outside the tent).

So I was all excited when I finally put everything back together and I fired up the new fan. Its loud as hell (sounds like a jet) and was sucking some serious air through the light now, so I was hoping when I zipped up the tent the temps would be a lot lower than they were with the small 6" 250cfm duct fan. I was very disappointed, the temps inside the tent were now 7 degress higher than the temp outside the tent. So I spent $220 and three hours cursing to lower my temps by 2 degrees, mad lame. I was actually astonished, because this new fan feels 10 times stronger than the old crappy one.

So I'm not sure now if the DR80 is just too small for a 400 watt light, or if the light I have is just stupid and emits an abnormal amout of heat. I actually bought my light from HTGSupply also, its the 400 watt HPS with air cooled hood (ballast outside the tent).

Somebody hellllppppp