IODINEIodine is a trace element with an average seawater concentration of 0.05 ppm. Iodine is an essential element for all inhabitants in your reef aquarium, promotes enhanced blue colouration in your coral and aids in the cell functions and sharing of nutrients between them. Invertebrates with exoskeletons require Iodine for malting and forming new exoskeletons. Directions:PROFESSIONAL USE ONLYThis product is to be used in conjunction with calibrated testing equipment or ICP-OES to determine depletion.2 drops (0.1ml) will raise 100L of aquarium water by 0.03 ppm. Ingredients:Concentrated Iodine30,000ppm CAUTIONKeep out of reach of children and pets. Not for human consumption. For marine aquarium use only. StorageKeep out of direct sunlight.Always secure cap on.