Abstract: In sand type filters, a pipe is often diposed beneath the surface of the sand bed and is rotatable on a vertical axis, located in the middle of the length of the pipe, horizontally and has nozzles extending along the trailing side of the pipe on each side of the axis of rotation. When these nozzles are supplied with fluid under pressure they cause the pipe to rotate and the water from the nozzles will agitate the filter and wash the soil therefrom, which can then be removed from the filter. A nozzle for this purpose is illustrated in my U.S. Pat. No. 3,351,292 and the present invention represents an improvement thereon by providing additional passages for fluid from the nozzle which not only assist in impelling the pipe in its rotary action but also provide for increased agitation of the filter bed.