DescriptionThe Biochemical Filter has the best effect on decomposing the excrement and the forage leftover.Its multi-porous feature will avoid blockages and provide the largest adhesion area for bacteria.The material has great thickne, it is durableVery suitable for using in freshwater and marine water.Can be cut any sizes as your needed.Lightweight & softne design.Excellent water permeability.Cultivate the nitrifying bacteria for biological filtration.Dense shape makes it effective to avoid residue.Can be used again after cleaning100% & unusedAdvise: Rep the bio-sponge three month, to ensure the filtrating effect as well as the growth of the nitrifying bacteria.Note: There may be an error of 0~2cm in manual ,Those who mind should buy with caution.