Ensure the air pump is plugged in.

Ensure there are no blockages in the air hose assembly and all valves allow air passage. If no air is produced by the accessories in the aquarium, remove air line from the pump and ensure air is being produced.

If the air pump produces no outlet, by far the most common problem encountered with any air pump is a ripped or weakened diaphragm. Inspect the diaphragm for tears or rips. Any opening in the membrane will make it impossible for the pump to produce air for aeration purposes. Always inspect the diaphragm first before replacing other parts in the pump.