Beano wrote:
@Elaine - my filter sponge in the new filter is not like a usual sponge
- it's more like plastic steel wool... so when I clean it most of the
brown junk comes off. If this happens, does this mean that the
bacteria are getting washed away too? I just find it hard to believe
that the new sponge will hold as much bacteria as the old one. Perhaps
I will get a better sponge and cut it to fit my new filter.

It should be fine. Nitrifying bacteria tend to cling to surfaces. Most
of what you're washing off are particles of food or poo covered in
heterotrophic bacteria. My plastic bio-balls in my pond are more like
what you're describing. I rinse them, a lot of stuff comes off, and
they look mostly clean but still slimy and a bit more brown than they
started. They seem to hold plenty of bacteria, despite looking clean.

--
Elaine T __
http://eethomp.com/fish.html '__
rec.aquaria.* FAQ http://faq.thekrib.com