API Crystal Size 6 Bio-Chem Zorb. Provides a home for massive colonies of nitrifying bacteria that rapidly develop a biological filter in both fresh and saltwater aquariums. Space-age porous polymer allows for rapid transfer of oxygen and water.
Available in 6 sizes: Size 1, Size 2,and Size 3 for the RENA internal filters. Size 4, especially for the nexx™ filter. Size 5 (treats up to 75 litres) and Size 6 (treats up to 210 litres). API Crystal.