Refuel by PolypLab is a water additive for reef aquariums. It is meant to boost water quality and supplement coral growth. Refuel is a bacterial food source consisting of a one-of-a-kind fusion of organic carbon sources augmented with healthy amino acids. This formula is carbon-based, safe and highly effective, steadily and gently improving water quality over time. The delicate, slow rate of change ensures no negative impact on your coral and other inhabitants, making this a great product for the careful coral keeper.