Juwel Cirax Bio Filter Media is a high-quality ceramic granule biological filter media designed for use in the Juwel Bioflow internal filter system. Featuring a highly porous surface structure, Cirax creates the perfect conditions for large colonies of beneficial nitrifying bacteria to establish and thrive, providing outstanding long-term biological filtration performance for freshwater aquariums. As a biological filter media, Cirax works to break down harmful ammonia and nitrite compounds, maintaining safe and stable water chemistry for fish, plants, and invertebrates. Cirax is an optional upgrade for the Bioflow filter system and is recommended for hobbyists looking to maximise biological filtration capacity. Easy to install and long lasting, Cirax should be replaced approximately every twelve months. Available in Compact, Standard, and Jumbo sizes to suit the full range of Juwel Bioflow filter systems.