Keep your Fluval Nano Filter working effectively and provide mechanical and biological filtration with Fluval Nano Bio-Foam Filter Media. Mechanical， chemical and biological filtration are essential to keeping your aquarium clean and healthy. Fluval Nano Bio-Foam Filter Media performs double-duty， trapping debris inside the filter chamber during mechanical filtration and encouraging the growth of beneficial bacteria in its large surface areas to facilitate biological filtration. Designed to fit inside the filter chamber， Fluval Nano Bio-Foam Filter Media flows water efficiently， clogs less and provides long-lasting filtration.