Nature's Ocean Atlantic Crushed Coral Gravel with Aragonite

Nature's Ocean Atlantic Crushed Coral with Aragonite #4 20LBS Benefits of Atlantic Crushed Coral: 100% from the Ocean Floor. Natural crushed coral gravel. Maintains superior pH and marine chemical balance. Provides maximum surface area for biological nitrification. Scientifically graded for uniformity which provides maximum water flow and aeration. Prevents anaerobic (Dead Spots) in Bacteria bed. Completely chemical free. Pre-washed (minimum rinse required).