Aquascape BioBalls Biological Filter Media supports effective biological filtration by providing textured surface area for beneficial bacteria to grow and colonise. Each ball offers 19 square inches of surface area, and the centre channel allows the balls to be strung together, making cleaning quick and simple. BioBalls Biological Filter Media will not break down like traditional biological media options, providing years of trouble-free use without replacement. The paddle wheel design breaks water flow, helping to de-gas the water and maximise dissolved oxygen levels. Compact size allows for placement into smaller spaces.