Royal Nature Marine Salt is a premium tropical sea salt for coral reefs. Royal Nature Sea Salt is made with evaporated sea water and so contains only those trace elements which occur naturally within the ocean preventing a build up of unwanted metals and chemicals. The formula has been specially developed to closely match the levels of natural sea water where your fish and corals come from paying special attention to the ionic balance and ensuring ideal parameters for Calcium Alkalinity Magnesium pH and Potassium as well as many other micro-elements. The result is a fast dissolving salt mix with an excellent balance of naturally occuring beneficial trace elements. Royal Nature Marine Salt is free from nitrites phosphates silicates and other unwanted metals and chemicals. 23kg bucket.