This Strainrite innovative bag is all set up to add carbon, resin, clays or chemicals to filter through. It is designed with an inside impervious side wall forcing the liquid to pass through the entire column. The contamination is conveniently trapped in an easy to dispose bag. The clean effluent passes through the bottom and back into your system. The top features a zippered disc so filling is easy. Call your sales person today for more technical support.