Equilibrium is specifically designed to establish the ideal mineral content for the planted aquarium. Equilibrium is ideally suited for use with RO (reverse osmosis) or DI (deionized) water or any mineral deficient water. Equilibrium raises the essential mineral/electrolyte content (General Hardness) of the water to balance with and promote stability of the carbonate hardness without the introduction of chloride or sodium (both can be detrimental to a planted aquarium at elevated levels). To maintain KH, we recommend Alkaline Buffer. Equilibrium and Alkaline Buffer are all that is needed to maintain the ideal mineral/electrolyte balance in the natural planted aquarium. Elemental potassium is present at a concentration of 195,000 ppm. Archaic fertilizer laws force us to list potassium in terms of equivalence to a material that is not present (K2O) rather than the more scientificaly sound method of simple elemental equivalence.