I use CO2 on the 2nd and 3rd weeks ,but some are running straight thru the flower stage to 1st-6 weeks. I’m using compressed CO2 off the beer truck with a rad controller set at 1475 as to not go over 1500 ppm of CO2. Running an old dehumidifier out of a electrical room have to run 24-7 when I use the CO2. Any opinion would be helpful for this next run.