This filter media aids in the growth of beneficial bacteria, which help establish a healthy ecosystem in both fresh- and saltwater aquariums. Help create a healthy home for your underwater friends with this API Bio-Chem Stars Filter Media. The filter media's porous polymer surface helps promote the growth of beneficial nitrifying bacteria, which aid in the establishment of well-developed ecosystems in both fresh- and saltwater aquariums. For use in fresh- and saltwater aquariums and filters Aids in the growth of beneficial nitrifying bacteria, which help establish a healthy ecosystem in many aquariums Porous polymer allows for rapid transfer of oxygen and water