JBL Cermec is a filter medium consisting of porous ceramic pipes suitable for use in freshwater and saltwater aquariums. JBL Cermec can be used as a mechanical prefilter medium for coarse particles or as a biological filter medium. The hollow structure provides ideal conditions for beneficial bacteria, whilst at the same time allowing excellent rates of water-turnover.Ceramic material frequently used for mechanical filtration.For use in fresh- and saltwater aquariums.As pre-filter medium, protects the biological filter material from rapid silting.