Multi-balls 60 pcs, bucket. Biological-chemical filter material for fresh and saltwater aquaria. Multiballs are a filter medium in which the biological function can be combined with a desired chemical filtration. Their properties ensure a large surface area and good water distribution. The secret of the Multiball is that it consists of two half spheres that can be easily separated. The outer surface provides a perfect site for the formation of bacterial colonies for biological filtration while inside the Multiball is a cavity which can be filled with numerous types of chemical filter media. Depending on the requirements of the aquarium's inhabitants, Multiballs can be filled with activated carbon (carbolit), antiphos, zeolite, hydrocarbonate, or peat granules.