Actually, it's quite easy to cut the sponge to fit. They also make a
floss which is in sheets and meant to be cut to fit. Cut the center out
(for your riser pipe) and then cut from the center to the outside (so you
slip it around the riser, and not over). You do not need a perfect fit,
but it should be snug, and any gaps will lower the operating efficiency.
Depending on the material, cut it slightly larger (about 1/4 to 1/2")
than the size actually needed.

You would not fill it with small pieces. These sponges are open cell, so
the water is supposed to travel through them. Water going around them
would greatly reduce their efficiency as a mechanical filter, and
significantly reduce their biological capability (imo).

NetMax

"Jim Morcombe" wrote in message
...
Can you fill it with small pieces of sponge or do you have to somehow
cut
the sponge to size?

Jim

Freda wrote in message
...
Jim Morcombe said

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

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

Don't use filter wool, instead use sponge. This will last ages (a
year
or more) and it certainly should not be thrown away as this is were
your
friendly bacteria will be living. You just clean it as required in
old
tank water - I do mine at the same time as a water change.


Do they work? Is it worth using?

Yes and yes - depending of course on your set up.


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