Patent ID: 7789553

Claim:
A method for operating a circulation system for a body of water to aid in reducing surface plant growth, said method including the steps of: (a) providing a flotation platform, a dish, an impeller, and a draft tube extending downwardly from said flotation platform and having upper and lower end portions, (b) operating the impeller for a period of time to draw water and plant growth adjacent the surface of the body of water downwardly through the impeller into the depths of the body of water and outwardly of the flotation platform wherein step (b) includes the further limitation of rotating the impeller for said first period of time in a first direction about an axis, and (c) rotating said impeller about said axis in a direction opposite to said first direction after said first period of time wherein step (c) draws water from adjacent the lower end portion of said draft tube up through said draft tube to said dish and said method includes the further limitation of maintaining said dish completely submerged under the surface of the body of water during step (c).