Specifications include, but are not limited to: The filter media support gravel and filter sand shall be packaged in sacks
weighing no more than 1½ ton or a 2-ton super sacks. The gravel shall be hard siliceous material having a saturated-surface-dry
specific gravity greater than 2.5. The gravel shall be washed and graded, and be free of shale, mica, sand, silt,
clay dirt, and organic impurities.