Thrive Magnesium is designed to increase Magnesium and correct ionic imbalances in your marine aquarium. The chemical management of salt water, reef aquariums is a delicate balance. The Thrive products and Thrive Analytics were created to help you simply assess and adjust the balance of your saltwater aquarium system. Thrive Magnesium is a saturated solution of magnesium chloride and magnesium sulphate. This means you won’t find this blend of magnesium any stronger. Magnesium keeps calcium and carbonate closer to super-saturation levels by holding on to a free carbonate ion. Corals use small amounts in building their skeletons.