Absolue Green is a highly concentrated iron solution which helps to bring out the intense colouration of SPS corals, especially green. Iron occurs in trace levels in seawater but is quickly used up in closed systems such as our aquariums. SPS corals are less likely to experience rapid tissue necrosis (RTN) when supplemented with iron.

Iron is essential for the formation of green coral pigments in SPS corals and also essential for photosynthetic organisms such as zooxanthellate, macroalgae and mangroves.