ok, thanks for the advice- iv read about it and it says you can go as low as 60 with lights off but its ideal to keep temps 75f lights on and 65 lights off, its just hard to get them stabalized- any sugestions to keep the room a slight bit warmer, its a walk in closset? im using a fan cooled 400 watt hps and when i turn the fan off it goes way too high!! is the any cheap to run heaters about?? iv heard of some type of cool tube thing??