Jack's Magic JMFIBER18 18 oz The Filter Fiber Stuff combines high performance, outstanding value, and environmentally friendly features into one great product. When used as a safe alternative to DE in DE filters, The Filter Fiber Stuff requires less than half the amount of product (by weight) than needed when using DE. It can be used to enhance the filtering performance of sand and cartridge filters as well. The Filter Fiber Stuff is non-toxic, making it safe to handle and store.