Our live sand is cultured in our systems and is well seeded with both bacteria and other micro fauna. This is not bagged sand, this sand is taken from one of our coral tanks that has been running for 15+ years. Consists of an assortment of grain sizes Aragonite sand, fine grain and larger. Many hobbyists keep a sand bed of 1-3 inches deep for nutrient control and biodiversity. Live sand is sold by the pound in any quantity and is shipped with water. We do not recommend rinsing before use. There will be a layer of silt in the bag due to collection from our aged system.