How to use an air stone for aquariums

An air stone is a small, weighted bubbler that produces very small bubbles in the water. This simple accessory helps to gradually diffuse air into the tank, improve oxygenation of water, and minimize the amount of bubbling noise you’ll hear. You can use an air stone by itself or in conjunction with a sponge filter to improve the efficiency of the filtration. The air stone creates a steady stream of tiny bubbles (instead of large, intermittent bubbles) that produces constant lift in the sponge filter – much like a continuously running escalator (versus an elevator that starts and stops all the time).

This diagram shows where an air stone goes inside a sponge filter to optimize its performance. To install an air stone inside a sponge filter, read our sponge filter installation guide.

For more information, read our full article on air accessories.