The AZOO Active Filter 4 in 1 can be used for both fresh- and saltwater aquariums. Its surface is highly effective. The bio-membrane improves the metabolism of beneficial bacteria and is also recyclable. The ionic silver has antibacterial properties, while the far-infrared active filter improves the water quality and ionic filtration removes or neutralises suspended matter, including free radicals and pathogens, for the benefit of the fish.