Enhance your finned friends’ underwater habitat with CaribSea Ocean Direct Original Caribbean Marine Live Sand. This substrate uses "Sea-Breathe" technology， which preserves original marine bacteria on a moist packed sand. Every grain is infused with bacteria and encapsulated in a thin film of real seawater. The thin film is open to the atmosphere for unparalleled gas exchange， which results in high counts of natural and beneficial bacteria with a non-toxic buildup of metabolic by‑products. With millions of bacteria and a beautiful aragonite substrate， it provides your scaly friends with a thriving， natural aquarium balance quickly and effectively. Every bag contains a 0.25-6.5 mm grain size and is alive with up to 1000 times more beneficial bacteria than other preservation methods.