Marina Internal Filter i25 i110 / i160 Cartridge Marina Internal Filter i25 i110 / i160 Cartridge – A134 – Marina Power Cartridge for i25 internal filter – 2pcs: Marina i25 replacement Power Cartridge, made specifically to fit inside the Marina i25 internal filter. Its unique design forces the water to enter through the centre of the cartridge. As unfiltered water enters the two-chamber cartridge, it first passes through the zeolite chamber. This will then remove toxic ammonia. The water then enters the activated carbon chamber, where pollutants and odours are removed. The water then enters the floss layer, which traps dirt and debris. This unique flow of water results in a crystal clear water. For best results, replace every 4 weeks. This package contains 2 Power Cartridges. A308 – Marina i110 and i160 Internal Filter Refill Cartridge – 2 pcs: The Marina i110 /i160 Replacement Power Cartridge, made specifically to fit inside the Marina i110 and i160 internal filters. The outside of the power cartridge features polyester foam to trap fine particles. The inside chambers contain carbon to remove pollutants and odours. Also zeolite to eliminate toxic ammonia for a cleaner, healthier aquarium environment and crystal clear water. Note: For best results replace every 4 weeks. For model i160: Do not replace both cartridges at the same time in order to ensure constant presence of beneficial bacteria. Click here for the Marina i25 / i110 / i160 Internal Filters!