Over time the tiny pores in the air stone can become blocked by dirt and lime scale preventing air from getting through properly. Depending on your local water supply and the conditions in your biOrb an air stone can last anywhere from 3 months to 3 years. Changing the air stone from time to time is advisable.
This porous pond air stone helps to distribute the air that is pushed into it maximising oxygenation of the pond water. It accepts 4mm and 6mm airline.
