I am stuck in a little pickle. I have about 15-20 plants in flowering at any given time and currently use (2) 400w HPS. Growth is fairly slow and has been producing rather small buds. So I want to add another 400w HPS or 2 and contain it all in a grow tent. I planned on having all of the lights lined up in a row. Will a 10x5x7 do the trick, or should I go bigger (8x8x7 or 10x10x7)? Also, the lights I use now are NOT air-cooled and won't ever be. What type of fan/s will be needed to keep such a room at the ideal temp for the plants? I plan on getting an 8" can fan for the exhaust and 6" for the intake. Sound about right? Any help here would be GREATLY appreciated as I'm looking to make this change yesterday.... Thanks guys!!
Well you have 350 cubic feet in your grow space. So you need at least a 350 cfm fan. Its not the inches that matter, its the cfm's. 350 is the minimum you want. I am going to be using a 265 cfm fan in a 41 cubic feet grow area, so I have enough to remove heat as well. So you probably want at least a 500 cfm fan or better, plus an in take fan, plus an oscillating fan inside to even begin to remove enough heat from 3 400W HPS. At least from all the advice I have been given anyway. Thats a lot of heat being generated. I also have an uncooled 400w HPS and I know how hot that sucker gets, I can imagine what 3 will produce.