Water purification in a closed and relatively small tank, such as an aquarium, is the responsibility of every aquarium owner, especially if their passion is to breed ornamental fish. They are particularly vulnerable to any pathogens that contaminate the water, depriving it of its crystalline appearance and causing unpleasant odors. The water that is pumped into the filter is in constant contact with the media, which allows it to be regularly and quickly purified. It is the aquarium owner's task to take care of replacing the filter media, which get washed out with the flow of water.