i have one off these and must say the flow is really awesome. the noise for the controller is very irritating its due to bad design of the fan in the controller, very small blades thus needs to run at very high speed to do the work, but i suppose if the controller stays pretty cool the little fan wont come on as its just a cooling fan. as for the pump itself its simple its a servo motor they do tend to make that noise, the pump (motor) would be much bigger to produce that flow if it where not a servo. servo motors provide tremendous power outputs with little power input. thats why most forms of robotics etc use servo motors
