Fluval 404 Noise

#1
Hello, I inherited a Fluval 404 with a 90gal tank and it had been running fine, although it hadn't been cleaned in a while. I finally got the time to take it apart and learn to clean it and then put it back together, and now it is making a horrible humming, rattling noise constantly. I'll try and take it apart again but does anyone know what to do about this thing? I've seen other people having this problem but have found no follow ups with what to do or what is causing it.

thanks
 

Purple

Superstar Fish
Oct 31, 2003
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#2
yeah - the 404 is the only one that makes a noise - sounds like a knackered air-pump :)

A couple of possible reasons -

Air in the can, small bubbles yet to blow through, crank the primer about a bit to loosen them up.

Impellor well and blades need a thorough cleaning - they get covered in in that brown slimy stuff and loose their effectiveness

Impellor cavitation. - Not as far fetched as it sounds....if the media sponges are clogged, the impellor will whiz around but not be able to draw water through - this causes cavitation (just like on a sub).

A less likely (but still to be considered) possibility is that the water flow is causing ceramic or stone media to move about, creating that graunching sound.

I have also had some sucess in the past with simply switching the filter off and on again - somtimes the re-start reduces the noise considerably - but remember the 404 was never a silent runner like the 204's are.