I recently purchased these two filters (fluval 304 and 403) used. They work fine but the pump makes a kind of plasticy grinding/clicking sound. ??? I have 2 404's that work great and I can hardly hear them. Is this sound normal for the old 303 and 403's? I wondered if they needed some kind of maintenance as they have not been used for a few years.
Thanks for the help
Jade ;)
A couple of possibilities would be:
If the filters are at the same height as the aquarium, they are not able to fully self-prime themselves and you have air trapped at the top of the unit - you can test this by lowering the filter or by putting the filter on its side. (you may get some leaking when on its side)
There may be damage to either the impeller (missing blades) or a bent impeller stem - in either case the part would have to be replaced if it is damaged.
Considering they are older filters, the O-rings may be dried out and allowing air to enter the unit. I believe the 303/403 have three O-rings (in-take, out-take and main canister) - Hagen sells a silicone lubricant for this purpose. (I have heard of people using very small amounts of vaseline, vegetable oil, or silicone grease for this purpose but I cannot say how safe/effective it is)
When you check the impeller and impeller shaft for any damage take some time to clean these parts (if they are ok) and the impeller chamber, basically all surrounding parts. If it is an old filter then it could be just dirt preventing a smooth run.
Thanks guys for the ideas. I'll try lubricating the o ring and cleaning the impeller. The filter is lower than the tank but just barely. There was a kink in my hose.
:)
Jade