aquaclear humming

[DavidZ]

Take the lid off and see if it is still making noise

 

[CWO4GUNNER]

I had to order a new impeller for my AC 70 the hole that the impeller magnet sits on in is "out of round" so the impeller rattles. Check the slop between the magnet hole and the impeller shaft, its its a little sloppy, time to get a new one.