This filter came with the tank, I think it's a rebranded Tetra Whisper?
When I first got it, it made a vibrating noise that drove me nuts, but I figured out how to stop that.
Well, now it's making some other noise. It isn't really like it has something loose or trapped bubbles. I've taken it apart tons of times to make sure it isn't clogged anywhere, I've push and poked everything I can and nothing makes the sound stop. It isn't the lid making the sound, because the lid isn't on right now and it's still doing it.
I tried putting some fabric between where the filter rests on the tank to see if it muffled it but nope, still just as loud. Sometimes it gets louder, then a bit quieter (though not quiet by any means).
How do I quiet the noise? I'm sure when I add fish and ADFs to the tank the noise will drive them nuts too. Do I have to just suck it up and get a new one?
I've also noticed water flows back over the top a bit instead of going through the filter cartridge. I've taken the cartridge out and rinsed in a bit of tank water but there's no change.