Red Sea Reef Colors D is a Bioactive Minerals Supplement and is part of the Red Sea Coral Coloration Program. Reef Colors D Supplement is part of the complete range of complementary major, minor and trace element complexes which together provide the needs of corals. Reef Colors D contains a blend of trace elements that are associated with many biological processes, one of them being the production of the purple/blue pigments in the soft tissue of corals.