Buy Bulk and Save. Why pay more for a fancy container when you can buy our high quality bulk Granular Carbon. The only difference between this and the name brand lines is the packaging. We will measure out the weight ordered using a Legal for Trade scale, place in a new poly bag and box it up for shipping. A quick rinse is needed before running the product in your system. Granular Activated Carbon based on bituminous coal provides the best combination of pore size, large particle size, high surface area, low ash, and hardness for chemically filtering aquarium water. In addition, test results indicate no leaching of phosphates. The high hardness level of this carbon prevents the dispersion of particles throughout the aquarium which can occur with softer grades of carbon. The large particle size facilitates water movement through the carbon and helps prevent the removal of planktonic food organisms via mechanical filtration.