MarcoRocks Key Largo Dry Rock 20 Lb Box 20 Lbs Total Per Box - about 5-6 peices. Great for Saltwater, A Reef Tank & Freshwater! Key Largo is a once live natural reef rock that is cleaned and sold dry. Environmentally friendly, Pest and organic free. Key Largo rock is a "green" product, because it is not harvested from a marine environment it has no negative impact on our delicate reef eco system.