Absolue blue is a highly concentrated iodide solution which helps to improve the colouration of SPS. It contains a safe, stabilized form of Iodide available to corals for rapid absorption. Iodide is one of the most important elements but is often short in supply in the reef aquarium as it is depleted very quickly in a closed system.

Iodide is essential for the formation of blue coral pigments in SPS, especially montiporas, millipora and acropora. Iodide also helps to protect SPS corals against tip burn.