Tropic Marin Synthetic Sea Salt: "Marine fish and invertebrates are extremely sensitive to impurities and pollution and the most important factor in maintaining a thriving marine aquarium is the purity of the salt water used." Tropic Marin was first formulated in 1965 and since that time, it has been continuously improved as more precise analytical methods have uncovered the many subtleties of natural sea water. It does not contain any phosphates or nitrates and is manufactured from absolutely pure pharmaceutical grade ingredients, 98% of which are from natural sources. Using a highly sophisticated process of solid solution mixed crystals, each grain of Tropic Marin contains the exact mix of 70 trace elements found in natural sea water and a unique production process ensures that all these trace elements are maintained in solution, avoiding selective precipitation. Special hydrates are added to ensure super solubility in tap water. Our packaging is 100% vapour proof which guarantees that no impurities from air or other gases can be absorbed whilst in storage, keeping the salt fresh and lump free. Tropic Marin Sea Salt is chosen by many of the world's leading public aquariums, professional institutes and hobbyists - it's the natural choice! We Also Stock Tropic Marin Pro Reef Salt