It works as a biological filter media, aquarium biofilter is excellent interaction between air and water and gas exchange. The bio-balls can give a nice living environment for beneficial bacteria where they can settle and be fed by water and oxygen. They will also promote gas exchange and increase dissolved oxygen levels. So as to form a good ecological cycle. By the way, the material is superior at effectively removing ammonia & nitrites that hurt fish and cause unwanted plant life. You'll be surprised how clean your tank or pool is when using this aquarium filter. Bio-balls do not require replacement unless damaged or destroyed, Using the scientific method, and reasonable filter material, the filter media works better.
Good quality seems like they are helping only used a couple so far. Pamela. Wilson, OK. Sun Apr 25 2021