TriVitro VFA 50 lb Vitroclean Aquatic Glass Filter Media is made from 100% recycled glass. It is crushed, dried at 250 deg F, and screened into various sized fractions to achieve optimal filtration properties. Specifically engineered for high performance, high demand applications such as water parks and large institutional pools. Vitroclean Aquatic is certified to NSF/ANSI Standard 50 and is approved for use by all major filter manufacturers.