low hum on 6055

[willewonka]

I have two 6055's on a 7096 controller in interval mode. One is extremely quiet. The other has a low hum when it's at the higher %. The whole setup is only a month old. I was hoping the sound would go away but it hasn't happened. How can this be corrected? I want it to be as quiet as the other one.

 

[rvitko]

There are many possible causes. Assuming both pumps are installed in similar positions on the same surfaces of same thickness (i.e. one isn't on a thin acrylic overflow box and the other on a thicker glass wall) and both magnet holders have the rubber feet installed we can assume it is the pump itself that is responsible. I would start by swapping the prop assemblies between pumps. If thats is not the culprit the most likely culprit is the disk which is difficult to replace but not impossible, it sits at the bottom of the shaft and it must be removed with a pick tool, the shaft should never be pulled out, doing so destroys the pump.