Closed system set-up

I have a 12 x 12-foot room with 3,000 watts of HPS light. I use an air conditioner to regulate the temperature. Is it still necessary to vent the room when I have a CO2 system running as well?

You are controlling the CO2 concentration, heat and humidity of the air in the growing space, so there is little need to vent the room. The air can be cleaned of pathogens using an ionizer or ozone generator. A closed system has several advantages over an open system. Unless fresh air is filtered in an open system, it may harbor infections or even pests floating in the current.

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