Manufactured by Vanson HaloSource, Storm-Klear, a natural chitosan-based biopolymer made from crustacean shells, enhances the ability of sand filtration systems to remove suspended solids, heavy metals and other pollutants from water runoff on construction projects and other commercial/ industrial sites. As shown in the photo, Washington state's DOT used Storm-Klear to manage water run-off on this 12-acre construction site, using it to help get rid of fine sediment, phosphorous, oils and minerals, and making it safe for release into public water sources. Vanson HaloSource