Tropic Marin Synthetic Marine Sea Salt "Marine fish and invertebrates are extremely sensitive to impurities and pollution and the most important factor in maintaining a thriving MarineAquarium is the purity of the salt water used." Apart from being a favourite with millions of hobbyists around the world Tropic Marin® Synthetic Marine Sea Salt is also the salt used in Tropical Marine Centre's hatchery where more than 100,000 healthy clownfish are successfully bred and raised each year. Tropic Marin® is also the preferred salt of many of the world's leading professional institutes, hatcheries and public Aquariums including "The Deep" in Hull. • True to nature. • Contains all 70 trace elements found in natural sea water. • Manufactured from pure, pharmaceutical grade ingredients. • Nitrate and phosphate free.