Bacter Ball is a sphere shape substrate additive made from Bacter 100. You can place it on the substrate and inside the biological filtration system
More than 100 different kinds of bacteria are inside Bacter 100 in a dormant state. Those bacteria form microorganism layer inside the substrate. To be applied at the bottom of the substrate at initial setup, or for restraining the growth of blue-green algae, sprinkle directly on the algae.