What makes up the 'Fluker's Hermit Beach Sand Substrate?

Unlike the calcium carbonate "sand" often sold as hermit crab substrate, 'Fluker's Hermit Beach Sand Substrate  is a perfect blend of all-natural sand, coconut fiber, sea salt and probiotic. The silica sand packs swell and the coconut fiber helps with water retention. Calcium and sea salt are added to replicate the exact sand hermit crabs find in their natural environment. Finally, probiotic has been introduced to help maintain a clean environment.