No c02 if it is in a area where you live. Like a closet in the house. C02 can be deadly. It can be used and temps need to go up some but not rez temp, it still needs the 70 mark.She Looks better, keep using the h202 with your nutes. Your humidity need to come down to 40% or less to give max buds. It's all about tuning in and your getting there . Good work and keep us up on things. Last pic, she looks healthy, way to go.