Live sand is a type of substrate used in marine aquariums, consisting of fine grains of sand that are teeming with beneficial microorganisms. These microorganisms include bacteria, protozoa, and tiny invertebrates, which help maintain a healthy ecosystem by breaking down waste and recycling nutrients. In addition to its biological benefits, live sand can enhance the aesthetic appeal of an aquarium. It provides a natural environment for marine life, such as coral and fish, to thrive. When setting up a new aquarium, adding live sand can help establish a balanced ecosystem more quickly than using dry sand alone.