For clean aquariums With the medium-pored black carbon pre-filter foam cartridges, you can change the filter media of your Oase Bio Master quickly and easily. Moving water is essential for most aquarium fish, as this is the only way to ensure effective filtering and gas exchange. A certain degree of current is also known to them from their habitat and not least serves their well-being. The aquarium should also always be filtered to ensure consistently good water quality. With the Oase BioMaster (not included) you ensure effective filtering in your aquarium. Thanks to the medium-sized black pre-filter foam cartridges, you ensure optimal mechanical filtration, which also removes unwanted substances from the water and thus ensures a longer service life for all biological media. Thanks to the EasyClean pre-filter module, there is also no annoying removal of the filter - you can easily remove, maintain and reinsert the pre-filter module Every now and then you should replace the filter media in your aquarium filter in order to ensure consistently high filter performance: in addition to changing the water, maintaining the filter is also important. However, you should either change the water or clean the filter so that not too many useful cleaning bacteria are lost. You can wash the filter media about twice under lukewarm water and should replace them about every 6 months to maintain consistently good filter performance. The black pre-filter foam is tailored to fit the Oase BioMaster external filter so that you can easily and easily replace it.