Chairs = common noun; Roll-O-Rocker = proper noun. Harriet threw the stale cucumber sandwich in the trash can and fantasized about a Big Mac dripping with special sauce. Sandwich = common noun; Big Mac = proper noun. Because we like an attentive waiter, we always ask for Simon when we eat at Mama Rizzoli's Pizzeria.
Answer: Reef Sand is live sand when it is on the bottom of the ocean floor, it is here where the reef sand is alive. When the Reef Sand has been out of the seawater for a period of time and exposed to the airborne elements it is considered to be dead sand. (lacking nitrifying bacteria).
Artificial reefs and reef restoration. What is a reef? For review, a reef is a bar of sand, rock, coral, or similar material lying below the surface of a body of water. Most people immediately think coral reef when they hear the word reef, but there are many other types of reef. The below images show an oyster reef and a coral reef.