How do you fix air in the holding tank?

To fix air in the holding tank, first, identify the source of the air intrusion, which could be a faulty vent or a leak in the system. Next, check and tighten all fittings and connections to eliminate any leaks. If the tank has a vent, ensure it is unobstructed and functioning properly. Finally, you may need to purge the air from the system by using a pump or allowing it to naturally escape through the vent.