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