DENI-BALLS made from the special biological based plastic material and contain a long-term carbon and nutrtion food source for anaerobe bacteria. It will be using by the anererobe bacteria completely. In the absence of oxygen, the anaerobic bacteria metabolize the deni-balls material to accelerate the reduction to nitrates into nitrogen gas. These bacteria may reduce the nitrate to zero, then to reduce the water change, avoids the algae multiplying and make the cultivating life to be healthier.