Tent size is 120x120x180 with a 600Watt HPS. Inside I have an oscillating fan on the floor situated right next to an open air hole. At the top of the tent I have an air hole open which will be for the inline fan for air extraction, but at the moment the fan is not connected (should be tonight). When I put my thermometer on the floor under the light the temperature is 94F (edit, right now its 97.7 ). Far too high. The thermometer is around 33" from the light. When I put the thermometer in the middle of the tent the temps are roughly the same. I do not have the ballast in the tent, everything plugs in outside the tent. I have another small oscillating fan that I will put towards the light to try and cool that a little. Is the inline fan going to make any difference to the heat? If not I think I'm going to have to knock the ballast down to 400W.