Using Active Aqua Active Aqua AS3FLEX 3-foot flexible air stones from your air pump will help improve your plants growth by adding oxygen to the nutrients in your hydroponic, aquarium, or waterfarm systems. It releases thousands of bubbles that aerate water and transport toxins from water near the substrate to the surface for dissipation. Air stones will extend the life of your nutrient solution, help keep roots healthy, and promote exceptional growth. Bend into any shape you need to deliver air where you need it most! For use with 3/16-inch inside diameter tubing.