Removes ammonia/ammonium, nitrite, odour, tannins, heavy metals & organic toxins from aquarium water. Reef Essential ® Bio-Active Carbon™ is originally designed to be used in ultra-pure water sanitisation meant for human consumption. Bio-Active Carbon™ has a unique pore size to water surface area ratio to promote the growth of beneficial bacteria. The bacteria help to improve the effectiveness of organic removal as well as eliminate toxic ammonia/ammonium & nitrite. Bio-Active Carbon™ will remove organic waste, toxins, phenols (colour), heavy metals, chlorine & chloramine without leaching phosphate or releasing the molecules it has adsorbed.