Tropic Marin PRO-CORAL IODINE Lugol´s Solution for saltwater aquaria Of all the trace elements found in natural sea water, iodine is associated with the widest range of effects. Iodine prevents goitre as an important component of the thyroid hormone. It also is essential for the hardening of the chitinous shell of crustaceans. Corallinaceous red algae deposit iodine in surface structures and gorgonias deposit it in the axial skeleton. Experiments clearly show that PRO-CORAL IODINE improves the adaptation to light and the colouring of anthozoa, especially of hard corals. Due to its unstable nature in solution, iodine should be added to a marine aquarium on a regular basis. PRO-CORAL IODINE contains iodine in its most effective form, as elementary I2.