The Dupree Bay has One Single speed pump, and One dual speed pump. It also has 2 circulating pumps. one is for the water feature, and the other is for the ultra-pure water mgmt system. All of the bay series have one dual speed pump, and the others are single speed. The dual speed is for filtration purposes, every twelve hours the pumps kick on for 2 minutes, and then the dual speed pump runs on low speed for the duration of the filtration cycle.