CO2 generators and burners are an efficient way to add high amounts of CO2 to your grow space. While ambient CO2 levels are generally in the 350-400ppm range, many indoor plants will benefit from increased CO2 concentration. Grow room CO2 is created from a variety of sources. Generators …and burners take propane or natural gas and burn it for the CO2 output of combusted gasses. HTG Supply carries everything you need to help your plants grow with CO2, shop now across our selection of CO2 supplies.