Air stones are used in garden ponds to diffuse the air provided from air pumps. Without air stones, air pumps will pump few large bubbles of water into pond water. These few "large bubbles" do not increase dissolved oxygen levels. Air stones "diffuse" the water into millions of tiny bubbles that increase dissolved oxygen levels throughout the water column. Increasing dissolved oxygen in garden ponds and fish ponds throughout the water column serves many purposes:
- Ensures adequate oxygen for pond fish
- Decreases algae
- Increases beneficial bacteria
- Enhances fish digestion
- Can help with fish color
