Matala Biological Cubes - 1 Cubic Foot Bag - Pond Filter Media - Keep Water Clean - Years of Effectiveness - Cover Large Surface Area for Beneficial Bacteria - Fish and Plant Safe OFFER GREAT, LONG TERM FILTERING: Extremely versatile, Matala Biological Cubes effectively filter the water of ponds, water gardens and other waterscapes for years. Use these long lasting cubes in virtually any waterfall tank or bio filter! For simple handling and storage, the 1 cubic foot of cubes arrives in a free mesh bag. Various sizes and densities, the cubes are cut from sheets of Matala brand filter material. Cube and bag color vary. COVER AN ULTRA HIGH SURFACE AREA: This 1 cubic foot of filter media cubes spreads across about 525 square feet of surface area. Because the cubes have a high coverage rate, they allow for a high degree of beneficial bacteria growth! WEIGH LESS AND COST LESS: Compared to traditional lava rock and most other aquatic filter options, these biological cubes are much lighter weight. They are also more economical than traditional lava rock! CLEAN EASILY: An open design makes this filter media simple to clean. Just rinse a bag of the cubes with water from a garden hose as needed. SAFE FOR POND LIFE: Koi, other kinds of fish and plants are safe with these bio cubes. Because the cubes clean water, they improve the homes of fish and plants.