"Jim Morcombe" wrote in message
...
I inherited a "corner" filter. It is just an empty plastic box that
sits in
the corner and you fill it with "filter wool" and activated carbon. An
air
pump is attached to draw the water through it.

How long does the filter wool last before it needs to be changed?

Depends on the bio-load in the tank. Could be weeks or months.

Do you clean the filter wool and re-use it or do you just chuck it away
each
time?

Depends on the material. The soft cottony stuff gets thrown away. The
stuff you buy in a sheet and cut to size with scissors gets cleaned and
reused, a few times (depending on how dirty you let it get).

Do they work? Is it worth using?

This was the mainstay of aquarium filtration for many many years. It was
this, UGFs or a clunky expensive canister filter from Germany. Then they
invented a HOB box filter, which still ran on airstones. Yes *sigh* they
work. Is it worth using?.. depends on your application. Makes a good
quarantine/fry tank filter. Their drawback is that somewhere, you have a
noisy little airpump to drive it.

NetMax

Jim