Well im actually going through some issues wit that right now summer kills my grow room !! Its a basement and I partitioned off half and split it in half I have two 6x10 rooms each with 2 1k hid I run mh in veg and hps in bloom I vent my lights outside they constantly pull the air from the room across the lights and out into my furnace intake... and I use neg press to pull outdoor air into the rooms (to prevent odor leaks) but in summer the just pull from the other side of basement and I end with a room thats a consisent 85 granted I run co2 but it slows growth and risks hermies:-( but theres not much I can do and I had to get rig of my hydro cuz water temps were up to 88!!! I even moved a 55g rez to the coldest basement corner tried diff intakes u name it theres just nothing I can do I wanna run about 75 lights off temps hit around 70 to 75 but now fall is coming and once fall starts I run duct from my chimney in and can set my temps anywhere I want and its perfect no issues... getting close!! And I can set my hydro up again:-) all my girls are aslo suffering from nute lock out right now from my well water that is so bad its eventually screwing my ph but thats not nearly as bad I have crazy mg deficiencies and I didnt know what was going on turns out my water was so bad it was building up salts and bad nutes to the point of lock out and im scared to use bottled water cuz of ph issues ive heard of and lack of trace elements:-( any ideas anyone!??