Coral Essentials, Coral Power Nitrate Up is a concentrated, inorganic nitrogen source (50,000 ppm).  In bacteria driven systems it provides an essential nutrient source to assist in biologically balancing marine aquarium systems.  Increasing the available nitrate allows the bacteria present to naturally bring down phosphate levels while providing a food source for your corals.
 
In ULNS (Ultra Low Nutrient Systems) aquariums corals can become pale and unhealthy if they are starved of available nitrate.  Coral Essentials recommends using Coral Power Nitrate Up when your system is too efficient at removing nitrate.  Coral will be more vibrant and colourful when nitrate and phosphate are maintained at correct levels. Coral Essentials recommends running your aquarium at a nitrate level between 1ppm and 5ppm.