The patented Marineland Black Diamond Carbon is a highly effective, premium activated carbon designed to eliminate discoloration while simultaneously keeping your aquarium free of odors and impurities. It works fast and then stays in play for longer when compared to the competition. Each pebble of aquarium carbon is made from heat-activated, coal-based granules which are specially sized so that they won’t damage your filter impellers. This product will leave your aquarium water sparkling clean while improving the environment for healthy fish and aquatic plants. Black Diamond Carbon is proven to be more efficient than coconut, wood or peat-based carbons and works twice as fast as the competition. Big Al’s Pets offers Marineland carbon in four convenient sizes: 5 ounces, 10 ounces, 22 ounces and 40 ounces.