The PolypLab Genesis Rock is a high-quality filter media designed to enhance your saltwater reef aquarium environment by providing essential biological filtration and promoting beneficial bacterial growth. Each rock can support up to 350 gallons of aquarium water, making the 2-pack an ideal choice for larger tanks or those with heavier bio loads such as predator tanks. The rocks are specifically engineered to minimize leaching and dust release during rinsing, ensuring that they will not harm your aquatic life upon introduction into the tank. Additionally, these rocks can be utilized in both aerobic and anaerobic setups, making them versatile tools for managing nitrite, ammonia, and nitrate levels effectively.