Hydrosil HS-100 is a molecular sieve of zeolite. This particular zeolite is called clinoptilolite. Hydrosil offers the HS-100 in two standard U.S. Tyler screen mesh sizes, 4 x 6 and 6 x 8. The molecular ration of silicon to aluminum is 4.9. The bulk density of the material is 49-51 pounds per cubic foot. The hardness on the Mohs Scale is 4.0 and the specific surface area is 40 square meters per gram. The material is thermally stable to 650 degrees Celsius and is stable at pH’s as 1.0 and as high as 13.0. Approved media suppliers are Hydrosil International Ltd. or approved equal.