Max Flow: 1720gph / Max Height: 16ft 5 Controllable Energy Saving Power Settings Detachable Controller with Waterproof Union Safety Float Switch 0-10v Input for 3rd Party Controller The Reef Octopus VarioS water pump features a detachable controller module, high quality ceramic shaft and propeller bearing to reduce wear and tear, and the latest variable speed flow technology for refined control, enhanced performance, energy-efficiency and safer operations. Unlike the vast majority of circulation pumps which uses alternating current (AC), the VarioS pump boasts several key advantages over traditional AC pumps, namely, higher energy efficiency, safer operations at a working voltage of 36V and most notably, the variable speed control to adjust the ideal mix of air and water flow into the skimmer. Direct current pumps have several key advantages over traditional AC pumps. Most notably, you can control the rotational speed of the motor, thus electronically control water flow rates. DC pumps are also more efficient than AC pumps and produce less heat per volume of flow.