Abstract: An automatic swimming pool cleaning device (10) includes a flexible cleaning member (12) which is designed to contact an underwater surface of the swimming pool. A tube (14) is coupled to the cleaning member (12) for connecting the cleaning device (10) to a water vacuum hose via hose adaptor (19). Water and pool surface contamination is drawn from underneath the cleaning member (12) up through the tube (14) by suction to a water filter system before being returned to the pool. A flexible valve member (20) is mounted proximate a throat region (22) of the tube (14) wherein as water is drawn up through the tube (14) a decrease in pressure in the throat region (22) causes the valve member (20) to flex and momentarily interrupt the flow of water. The interruption to the flow of water through the tube (14) results in a momentary differential of ambient pressure underneath the flexible cleaning member (12) which enables the device (10) to move forwards incrementally along the underwater surface of the pool.