Co2, great stuff. Green air products and CAP make controllers that control the ventilation in your room for co2 enrichment. Are your lights air cooled? I would go with air cooled hoods to keep them on their own system to better control the heat. Make sure they are tight with nashau metal tape. You'll want to still use fans to keep the air circulating inside the room and use the soaker hoses draped above your plants to deliver the c02 as co2 is heavier than air. There is an equation for c02 enrichment in Ed Rosenthals book. I'll have to find it fer ya.