Key Features Genuine Oase Foams Replacement Filter Foams. Fits the BioMaster Aquarium Filter 1 x Orange Filter Foam 30ppi Keep your system healthy by reguarly changing media Genuine Oase Pre Filter Foams set, suitable for the BioMaster Aquarium Filter. The Oase BioMaster Aquarium Filter has a selection of Foams and Pre Filter media to help keep the water at its best as it passes through the system. Here we have replacement filter foam 30 ppi.