Abstract: A method and apparatus for controlling water impurity level and temperature uniformity within large water-containing reservoirs including a pump located in the body of water, the pump ejecting a jet of water therefrom and ingesting water at a point remote from said ejecting and an eductor positioned in the jet of water for pulling in low pressure water and flowing a stream of water therefrom providing mixing and circulation of water within the reservoir to remove temperature gradients. Water purity is controlled by a controller.