This filtration gravel offers extremely high pure silica content (>99% SiO2) and pebbles are sized #20 Flint.

The highly spherical shape of Nelsen's uncrushed gravel promotes good flow and even distribution. Being low in soluble impurities, it will maintain the quality of the treated water, especially when used with water softeners. To ensure a clean, quality product, all filter gravels are double scrubbed to remove all clay, shale and inorganic impurities.

Gravels are washed, dried and sized using PLC controls for consistency to meet the American Water Works Association B100 Specifications for Granular Filter Media.

NSF certified for Standard 61 – Drinking Water System Components & Materials.