MEDIAPOR g.270 Mediapor is made of a very porous ceramic that has a large surface area for the development of beneficial bacteria (Nitrosomas and Nitrobacter) to establish optimal biological filtration. The micropores of Mediapor offer a self-cleaning effect while keeping its outer surface smooth. The beneficial bacteria that Mediapor develops help to keep the water clean and clear, improving the health of the aquarium inhabitants. Ideal for all internal and external filters.