The ROI-E420 was especially developed with the enthusiast "in tent" applications and cultivators who need a compact led fixture that produces high photon output. The e420 is excellent for tent grows as it's compact design relieves growth space while still offering high energy output to the canopy producing exceptional yields during bloom. The E420 is also great when used as an effective veg device in large scale and commercial cultivation as the 3k full phase spectrum provides all the PAR required for all stages of plant life. It is not necessary to run CO2 with the ROI-E420. Nevertheless, supplemental CO2 between 450-800 ppm will be helpful and also increase yield capacity.