I have a maxi-jet 600 return pump and for the past few days it's been humming and buzzing loudly. It's very annoying because my tank is a nuvo 8 sitting right in front of me on my desk. Usually before I would just unplug it and plug it back in or shake it and it would stop, that isn't working anymore. Do I need to clean it? Or does anyone have any experience with buzzing pumps?