Liberty 2617411 • Different filter cartridges perform various functions: • Bio-cartridges with extractable filter pads offer the best colonisation conditions for the important purification bacteria. • 3D-active carbon cartridges, on the other hand, remove unwanted toxins and should be used especially after medical treatment or initial set up of the aquarium. • Included with each filter pack is always at least 1 large biofilter cartridge with 240 cm3 volume. • Depending on the model, also included are two or three extra cartridges. An additional after-sales product is the 3D-active carbon cartridge. • Also available are small bio-cartridges for a variety of uses.