Close the fan damper on the digiq about 1/2 way and close your top vent about 1/2 way and leave it there. My understanding is that the digiq will supply the needed airflow through the smoker and closing the top vent down isn't a problem. The digiq needs to be able to have total control of the fire. If too much air is moving through the smoker due to simple convection, the digiq can't do its job. I struggled with this on my first couple cooks with the same ATC.