I bought the filter 2 months ago on black friday with all new tank, heater etc, and started my tank a week ago. Currently cycling with new plants / no fish.
The filter is suppose to be quiet and that's the reason I bought it.
I needed it to be quiet, my girlfriend didn't want me to start a new tank with HOB because of that.
It's now been running for nearly a week and there is still noise. More like vibration.
I did everything to be sure there was no "air" in the filter or tube. I even reduced them.
There is rubber feet under the filter. But it feels like it's coming from the impeller head. I looked at the head, there seems to be some "loose" on the impeller but cannot say if it's normal or not as I have not seen any others.
The noise get out of the cabinet and we can hear it clearly in the living room and even upstairs at night.
Make watching the TV impossible.
I took two video with my phone. A bit difficult to catch with the microphone but you can hear and understand.
I also sent the video to fluval support. Hopefully I/they can do something about it.
But some people here might have seen or did something to fix this issue already.