Intensify White, Blue & Violet Coral Colour. Reef Essential® Bio-Gen™ is designed to provide bioactive halogens such as iodide, fluoride & bromide to help intensify white, blue & violet coral colour. Reef Essential® Bio-Gen ™ also helps to reduce coral bleaching, improve calcification and acts as a natural resistance improver. This product must be used alongside our Reef Essential® Bio-Enhance™, Reef Essential® Bio-Metals™ & Reef Essential® Bio-Kalium™ supplements as together they will provide the required biomolecules, major, minor and trace colouring elements. If wanting to enhance coral bone growth & density we recommend our Aragonite Enhancers™. Recommended total iodine concentration = 0.06-0.09ppm.