Check the listing for details. Large Aquarium Air Stones Fish Tank Round Air Disk Bubble Diffuser Release Tray. Condition: New. Listed at 6.88 USD. Large Aquarium Air Stones Fish Tank Round Air Disk Bubble Diffuser Release TrayBullet Points: Good Filtration: Sintered at high temperature, these air stones for aquariums are made of super hard golden steel sand, which ensures good bubbler diffusion and prevents clogging. Fine Bubbles: With fine bubbles and uniform air discharge, our air stones create more frothing for your aquarium. The highly dense pores also ensure a wider contact between the bubbler and the water surface, enhancing the oxygenation of your fish tank. Secure Fit: The air stones for aquariums have a firm attachment that doesn't fall off, creating bubbles and oxygen for your fish. They fit 4-8mm standard interface pipes and offer different sizes for your preference. Keeps Aquatic Fish Alive: By producing a gentle water flow and increasing the oxygen content and PH value of the water, this air stone creates a healthy and quiet environment for your fish. Oxygenates Water Efficiently: These air stones can create a steady stream of bubbles that improve the water flow in your aquarium. Before using them, please soak them in water for 15 minutes to activate them. If they get clogged with dirt, you can take them out and rinse them with water. They can be used repeatedly for a long time.