Fiber Clear is an environmentally-safe alternative to Diatomaceous Earth for use in D.E. pool filters. It's much more efficient than D.E., provides superior water clarity and, most importantly, its use entails none of the respiratory health risks associated with D.E. It's Made from hardwood cellulose fiber. Fiber Clear is completely organic and non-toxic and just a little Fiber Clear goes a long way. Fiber Clear beats Diatomaceous Earth in every aspect possible. It’s cleaner, safer, easier and less expensive.