The EHEHM Biofilter Cartridge Liberty is a high-performance replacement cartridge designed specifically for the Liberty series of hang-on filters (for example models up to 200 L). It features a porous foam material that effectively traps dirt particles while simultaneously offering an extensive surface area for beneficial nitrifying bacteria to colonize—a key process for biological filtration and maintaining water quality. This cartridge improves contact time between toxins (such as ammonia and nitrite) and bacteria, promoting healthier aquarium conditions. Ideal for both freshwater and marine setups, it’s recommended to rinse it gently every 10 weeks to maintain effectiveness and extend its usable life.