Abstract: An apparatus for use in fluid recirculation to, for example, mix oxygen-rich top water and oxygen-poor bottom water in a lake. Specifically, the recirculation apparatus has an enclosure with a wall defining an interior space and a closed end and an open end, the wall having a plurality of openings. Also included is rotating propeller assembly, a flotation device disposed within the interior space and attached to the enclosure, so that the apparatus is buoyant with the open end facing downward; and the openings are configured to be at or near the top surface of the fluid medium. The apparatus may also include a flexible anchoring system and controllers, including the use of oxygen sensors.