This form will calculate how much CO2 will be needed to fill a grow room to the required level. It will also determine how long it will take to fill at the given rate.
It will not calculate how often you will need to refill the room with CO2. There is no way to calculate how much the plants will use or how much leaks out! Usually you would want to refill just after an exhaust cycle or every 3 hours.
CO2 is an odorless, invisible, and non-flammable gas. It is also safe for humans in the maximum concentrations recommended for plant growth. The average level of CO2 in the atmosphere is about 400 PPM (parts per million). If the level decreases down below 200 PPM in an enclosed growing area, plant growth slows to a halt. Through the years of testing and research, the optimum enrichment level of CO2 for plant growth has been agreed to be about 1500 PPM. With CO2 enrichment, under good conditions, plant growth rates and flowering will increase 20-100%. CO2 can be used from seedling right through harvest.
*The air already has about 400 PPM (thanks Rich) so you only need to add 1100 PPM more to get the optimum level of 1500 PPM.