Each Bio-Rocks Package contains 0.5 Cubic Feet of Bio-Rocks. 

High surface area provides optimal environment for beneficial bacterial colonization. 

Bio-Rocks Media has all of the surface area but 25% less weight than lava rock and half the weight of gravel, expanded clay Bio-Rocks are the more stable, less abrasive alternative to heavyweight bio-media. 

Expanded clay is a lightweight, stable and less abrasive alternative to lava rock and gravel. Bio-Rocks are durable and easy to clean. 

Use a mesh bag to hold the Bio-Rocks, we recommend one mesh bag per 0.5 cubic feet. 18" x 22" mesh bags sold separately. Mesh bag part number 73990 (formerly BG2234).

Bio-Rocks have a 5-year warranty.