Air line check valve allows air to flow in one dirtection only and prevents water being sucked up into the air pump. Essential to preserve your pump and its warranty.
Stay safe with Aqua One Airline Check Valve! Easy and convenient to install so your aquarium can perform at its best! Ensure a check valve is used whenever an air pump is positioned at or below the waterline of the aquarium.
A check valve is a one way valve that only allows air flow in one direction. Hydrostatic pressure in an aquarium air line can cause aquarium water to be sucked up the air line directly into your air pump. This can happen even when the pump is positioned above the water line. Using a check valve prevents damage to the pump and is a requirement for warranty on your air pump.
Check valves also prevent accidental siphoning of your aquarium in the event of a power outage.
You need to be aware that adding a check valve does place some restriction on the air flow from your pump to the aquarium. A reduction in flow of up to 25% can be experienced depending on the condition and quality of the pump being used; and the type of check valve.
Have a look at this video on how check valves work.