Abstract: A system is provided for restoring and maintaining a eutrophied natural body of water such as a lake. The system includes an initial treatment or takedown phase to precipitate phosphates, if necessary. A second or final phase includes the utilization of a series of dispensers in the lake water and in the watershed area to continually add measured, slightly less than stoichiometric amounts of secondary phosphate precipitating cations, such as soluble complexes of trivalent cations, to continually inactivate phosphates, with hydroxo complexes, fluoro complexes and complexes of weak organic acids, including amino acids, being preferred.