An air flow control system for an agricultural product delivery system includes a sensor. The sensor is disposed within, along, or just before a secondary distribution manifold for measuring an air flow pressure therein. The sensor generates a signal in response to the air flow pressure in the secondary distribution manifold. The air flow control system also includes a controller which is operatively connected to the sensor. The controller is configured to receive the signal and to adjust the air flow pressure to the secondary distribution manifold in response to the signal.
