Airline Check Valve

The Airline Check Valve is a critical safety component for any aquarium aeration system where the air pump is positioned at or below the water line. During normal operation it allows air to flow freely in one direction — from pump to tank. If the pump stops during a power cut or failure, the check valve's internal flap closes automatically and blocks water from siphoning back through the airline tubing and into the pump motor.

Back-siphoning can damage or destroy an air pump in minutes, flood the cabinet below the tank, or allow tank water to drain if the airline runs below the tank water surface. A check valve costing a few dollars protects against potentially expensive pump failures and water damage.

The check valve fits inline on any standard 4mm airline tubing run and should be installed as close to the pump as practically possible, with the flow arrow pointing away from the pump toward the tank. It should also be checked periodically as the internal valve flap can wear and allow slow back-siphon over time.