Ceramic Filter Media Brick 4 Pack 3.6lb NanoSpheres Biological Filtration on July 19, 2026 July 19, 2026 NanoSpheres Technology each block contains over 5.5 million NanoSpheres. Bio filtration does not build overnight. #1,096 in Aquarium Filter Accessories. Rated for 100~150 gal / 14800ft surface area per box.