Breathing Bio-Ring Breathing Bio-Ring is mainly made of quartz glass, its porous quartz surface offer nitrobacteria the best biological environment. The outer surface of Bio-Ring is suitable for aerobic bacteria to multi-propagate and the inner surface area is suitable for anaerobic bacteria, leads to a denitrifying and nitrifying process for biological activity. It has larger surface area of 6-8 times than ordinary Ceramic ring. Suitable for fresh and marine water aquarium.