Tetra CV4 Check Valve

The Tetra CV4 is a check valve for the hose of an aquarium air pump. According to the manufacturer, it keeps water from entering the air pump, for example during a power failure.

The valve is meant for aquariums where the air pump sits below the water level. According to the manufacturer, it allows the pump to be placed beneath the water level without aquarium water running back along the hose into the pump.

The valve is simply fitted into the air hose. Cut the hose between the pump and the aquarium and insert the valve into the gap.