Do I need an air stone for my sponge filter?
An air stone is a small weighted accessory that diffuses the air from your air pump into smaller bubbles in the water. We recommend adding an air stone to the inside of the sponge filter to lessen the bubbling noise and make the filtration more efficient. 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).
For more information on sponge filters, read our full article here.