Nature's Ocean Pacific Coral Gravel - #5

These Pacific Coral Gravel #5 is heat sterilized and is 100% from the ocean's floor. It contains marine trace elements to reduce nitrates, maintain pH and increase carbonate hardness in your aquarium. This premium reef substarte is ideal for reef system tank bottoms, denitrifying anaerobic beds and can be used as extremely high surface area filter media. The Pacific Coral Gravel #5 features 2 to 3.5 mm grain size.