Nitric-Back Base(Lava or Volcanic granule) is from natural lava materials, through advanced technology processes , it is suitable for aquarium use. Porous structure provides Nitric-Bacterium the suitable environment to multi-propagate. Provide a good and stable water condition for the livestock by eliminating the toxic NH4/NO2 and etc? Help to maintain a good and stable water quality and the ecological system. Suitable for fresh and marine water aquarium. Rinse Nitric-Back Base(Lava or Volcanic granule) with clean water before use