Check valve for 4/6 air hoses

An indispensable piece of security.
Use non-return valves wherever your membrane pump is below the aquarium.

Product Information

Is your diaphragm pump below the aquarium?
In the worst case scenario, if your membrane pump fails (e.g. due to a power failure), your pool can empty itself via the air hose.
With a non-return valve in the air line
you are on the safe side.