On Mon, 14 Nov 2005 08:26:59 -0600, "Koi-lo"
wrote:


"Steve" wrote in message
.. .

I have large external Fluval filters of different vintages, and
Aquaclears. Both can make slight rattly noises, although otherwise they're
great filters.

## There can be air caught in the impeller well. Try tipping the filter to
release it. Also, look at the impeller magnet itself and see if it shows
wear. Hold the filter horizontal and see if that makes a difference.

As noted in another post, the quietest filter I've had was a
within-the-tank Fluval filter. I used a foam sleeve instead of the
disposable cartridge media for this filter, to preserve bacteria and
reduce costs.

## That may be the route you'll have to take.
I think it could be the size of the Fluval. I used to have a 304 and
it did not make much noise at all. I replaces it with a 404, which
makes some ratlly noises. You can hear it from few feet away. I later
added another 303 because the 404 is not big enough to handle 125 g.
You can tell the difference between these two in terms of noise level.
I guess the bigger one uses a bigger impeller which in turn makes a
bit higher level of noise.