Biofilter Media Spheres - 1.5" - 2 qt MarinePure Biofilter Media by CerMedia is the most technically advanced biological filter media available on the market today. Designed to be versatile and easy to shape, this bio-filtration substrate can be used in tanks, sumps, canister filters, DIY filters, trickle or shower filters, waterfall filters, and hang on back filters. MarinePure rids your aquarium water of ammonia and nitrites and reduces nitrate levels while also providing an ideal surface area for beneficial bacteria to thrive and multiply. As a result, fish waste and other harmful waste material are more readily eliminated from the water, creating a cleaner ecosystem for your aquatic pet(s). Thin Bio-Film Technology A specially designed porous surface with open, interconnected holes allows for the development of a thin bio-film. This bio-film provides key nutrients for beneficial bacteria to flourish. The open pores also allow bio-film to recycle and replenish easily without clogging the biofilter media, since water flows through the media rather than around it. Overall, MarinePure is a high performance bio-media that delivers great value by improving the quality and consistency of the aquatic ecosystem and water chemistry of your tank.