The Aqua One 5c Carbon Cartridge is a disposable filter cartridge pack for use in the Aqua One AquaStyle(AR) 980 aquarium. The Aqua One 5c Carbon Cartridges form the top layer of the trickle filter. A pack of three 5c carbon cartridges is supplied ( two large and one small for one full filter change) and the cartridges should be removed and discarded when blocked with fish waste and debris. This will usually be every four to six weeks. The Polymer ‘wool’ layer traps debris while the activated carbon removes odours and clarifies the water. An essential part of the Aqua One trickle-filter system.