Hello there! I am running 2 1000 watt HPS lights for 12 plants in a basement and I have no fresh air coming in the room. The plants are about 26 inches tall and nice and bushy in 7 gallon grow bags. I switched them over to 12/12 and they arent getting any bigger.... Is the lack of fresh air to blame? Also it is 24 degrees outside and that is one of the reasons I am not running fresh air in. any tips would help. btw room temp is 72 degrees! Strain=Grand daddy Purps