Bio Max Media. Suitable for ALL pond filters. Bio Max has excellent surface area (useable surface area of 1530 square meter/liter) for the growth of beneficial bacteria, resulting in a clean, clear and biologically-balanced pond. Its unique structure is designed to house the correct number of microspores perfectly sized to allow the beneficial bacterial colonies to reproduce and thrive, creating a bacterial sanctuary that maintains a biological in the pond water. Beneficial bacteria living in microtunnels and microcavities naturally eliminate ammonia and nitrite, which are toxic components that originate from pond inhabitants, decomposing organic matter, and run-off from surrounding terrain. It is recommended to replace every 6 months. Package 12.3 oz.