HOBBY Absorbex Micro (Glass Rings)Has an absorbent effect i. e. harmful substances are broken down by aerobic and anaerobic bacteria who are given an exceptionally large area of colonisation (approx. 765 m) by the material. Nitrite and ammoniac are absorbed efficiently, nitrate and phosphate are broken down significantly and the biological balance is assisted. pore channels of the sintered glass rings ensure optimal water and oxygen flow pore size provides ideal habitat for nitrosoma