Boyu Activated Carbon is useful to quickly and effectively remove harmful substances in your aquarium water. It contains charcoal, which works to eliminate foul odours and heavy metals from your aquarium. The charcoal has a strong physical adsorption which achieves the removal effect. It can also remove unsightly discoloration, and harmful organic substances from the water. It works to neutralise odours, heavy metals, purification and will create a softening effect to your water, and increase the water quality. This product is suitable for fresh water or a salt water fish tank.