Check Valve

Prevent water from siphoning out of aquarium Rubber valve for longevity Essential for power outages A check valve is used to prevent water from siphoning out of your aquarium. If water siphons out, it will usually damage the air pump and lead to water on your floor. In extreme cases, this can lead to fire if electronics are sitting in water.  If the air pump is positioned lower than the top of the aquarium, you absolutely need a check valve to prevent water leakage through the airline tubing. Cut the airline tubing somewhere between the sponge filter and the aquarium device, and attach the check valve in between so that the end of the check valve with the flapper (typically looks like a horizontal bar) is facing the air pump. If you install the check valve backwards, no air will flow when you turn on the air pump, so just flip the check valve around. Best practice is to place the check valve near the top of your aquarium. This stops the water at the rim instead of down near the pum