Reconstitute RO is a high quality, multi-component, broad spectrum mixture of all mineral ions including General Hardness (GH), alkalinity (KH) and all major, minor and trace minerals required for optimum health and longevity of freshwater fish, invertebrates and plants. When mixed with filtered water prepared by reverse osmosis, distillation, or deionization, it will convert those filtered waters into a natural environment in which all aquarium inhabitants will thrive. It has been used to raise discus and other freshwater fish, as well as keep whole systems in breeder, public and home aquariums. Reconstituting reverse osmosis, deionized or distilled water ensures complete user control over aquarium water parameters. Treating purified water with Reconstitute RO allows the user to customize hardness and alkalinity for the type of fish you're keeping. This is especially important when keeping and breeding sensitive or expensive species such as discus or wild caught fish. Using reconstituted purified water will also help solve many aquarium keeping water quality issues and prevent the entry of unwanted nutrients such as phosphates that are prevalent in public water supplies.