BioCliff has a porosity of 85% and a surface area of 1250 m²/litre. The structure is designed in such a way that both aerobic and anaerobic zones are formed, which enables the decomposition of nitrite and nitrate. The purely natural, siliceous rock is pH-neutral and has no effect on the hardness or pH value. BioCliff ensures crystal-clear water quality. It has an extremely large filter surface for the colonisation of filter bacteria. The different size of the material increases the retention time of the water in the filter and gives the bacteria more time to transform.