When taking cuttings/clones and in the 1 inch neoprene pucks, only the pump should be working and plugged into the "always on" . No air stones or air pressure at all or the cloner will leak. When the clones are in the hydro 12, the air stones should be working and the pump plugged into the "timed water". I always just turn my air on and off with the valve thats in the top. Dont know if this helps but..... Good luck!