Use with Filter---Provide Larger, Multi-Faceted Area for Support of Biological Filtration.The filter of each aquarium is limited, and the filtering space for placing biochemical balls is not too large, but it is the function of biochemical ball to make up for the lack of filtering space. Filtered Water---Because the biosphere is light in weight and easy to carry, it can be used not only in biochemical filtration systems in seawater, but also in biochemical filtration systems in freshwater.Great help to restore the natural water quality, and provide the most suitable living environment for your fishes. The Principle of Biochemical Ball ---It is to let the water through the space that is distributed in the internal zigzag, to prolong the of water, and to add the nitrifying bacteria attached to the multi-column structure to achieve the effect of biochemical filtration. Wide Application---Suit for biochemical filtration systems in freshwater, perfect for using in fish tank, pond and aquarium. Wide Application---Suit for biochemical filtration systems in freshwater, perfect for using in fish tank, pond and aquarium.