# Fluval 404 Rattling



## Guest (Apr 23, 2005)

Hey everyone, im new to the forum. My fluval 404 started rattling a couple of days ago. Ive had it for about 5 months now and i think something may have happened while i was cleaning out the filter. It sounds like the propellar is loose or something. It not really that lound, its just that my bed is near the tank so you can see why it is pretty annoying. I tried to fix the problem by playing around with the propellar but nothing seemed to work. Has anyone else had his problem with the fluval, I always remember it being pretty quite up till now. 
Thanks.


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## osteoporoosi (Jan 27, 2005)

Check if there is any air in the filter, shut it off and then turn it from side to side. Then plug it in again and see if there comes any air bubbles.


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## TANKER (Apr 28, 2005)

Rattling in a canister filter is typically caused by cavitation on the impeller. Cavitation is caused when you have an air pocket in your canister. A little trick I use to ensure a full prime is to plug in the filter after filling it as full as I can either direct or via prime, then cover the outlet with my thumb and increasing the head pressure on the impeller. This will force any air in the canister up the line and into your tank allowing your canister to fill and eliminate the cavitation.


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