I just bought the same controller, and when i hooked it up for the 1st time my Co2 readings are Appx. 850 ppm??
This is with NO Co2 hooked to the system yet! Can someone Please explain to me how my basement can had twice the average air Co2 without the tank being hooked up yet?
This is in a 5.5' x 6.5' room with appx. 20 15"-24" tall plants!
Thx