Aquarium Aqua Fish Tank Air Stone Diffuser Giant Large Huge Round Size Benefits of using air stone: It is widely used to drive various kinds of filters and equipment, for instance under gravel filters and a few sorts of protein skimmers. Fish tank that contain solid covers or close fitted hoods on top are prime candidates for stagnant air, low oxygen levels, and high levels of carbon dioxide. Nonetheless, for these types of set ups with an under gravel filter run by an air pump, the fresh air bubbles that come up through the uplift tubes help to get rid of these problems by provided superb oxygen along with other gas exchange opportunities. A power head works extremely well instead of the air pump and stones to work the under gravel filter, however, if the power head is not equipped with an aeration function, or this characteristic is not used, it can provide low oxygen and low PH. Whether having an under gravel filter or not, air bubbles aid to maneuver the tank water vertically on the way to the surface, aiding with oxygen and other gas exchanges. It is affordable way to move the tank water vertically. It develops a wall of bubbles that can look pretty cool in the aquarium, plus watching them can be quite soothing. Size: Approximately 2'' wide