SABL-050 50 lb Salt Filter Sand is composed of whole grains of crystalline silica of great hardness. Its grains are durable and dense, which allows them to be resistant to degradation. Each grain is washed, dried and sieved according to a very strict quality control process. Warwick Salt filtration sand is suitable for use in pressure and density filter feeders. It is also used in pool filter filters as well as in various industrial processes and auxiliary applications.