in winter,i put mine on rock pile bout 3 ft below in the shallow end ,the deep water one is shut off. from what i have read and learned, you want keep some do moving , keep ice open for gases, let some sun into the water for the plants and leave the deep part alone. it's mother nature's way to protect the fish from winter, the refuge of 50 or so degree of water in the winter in the deepest part of the pond.
