In The Swim Filterballs Blu Advanced Replacement Sand Pool Filter Media - 1 Pound 1 pound of Filterballs Blu = 100 pounds of #20 silica sand Lower working pressure = less energy consumed Material is 100% recyclable and filters to 10 microns Lasts 3-4 years and provides 45% greater flow rates Holds more contaminants eliminating floccing and reducing backwashes