Aquacity8482; Activated Charcoal Carbon in Free Mesh Media Bags for Aquarium Fish Pond Tank Canister Filter (4-Pack (4 lbs)) Removes odor, colors, organic pollutants to keep water crystal clear; removes toxic compounds from fish tank. Phosphate free. Safe for both fresh and saltwater tanks. Fast working and long lasting. Bagged in free mesh bag for easy handling and precise placement of carbon and ensure granular media not travel thru pumps and pipes. Bag size: 8" x 5.5". Zipper-designed; reusable. ****As with all carbon media, Rinse well till the water runs clear before use. ****