Rob,
Ok fine I take your word for it, but what is a sponge filter?
Around here the brand "Aquaclear" filter is popular. It is a
plastic box, that hangs on the tank side, with a siphon and a motor
pump arangement that recirculates the water through a open cell sponge
and a carbon or other media bags, and that's it.
Is this what you mean by sponge filter?
Nope, too complicated. We use a hollow cylinder of open cell sponge, shoved into a small plastic container of the same diameter which has a few rocks in it to hold it down. (You can use shell grit if needed). An airline is fed through the side of the cont
ainer to an air-stone. As air bubbles rise through the sponge cylinder's hollow centre water is drawn in through the cylinder's sides. That's it. We get ours from Eureka Aquarium Supplies in Queensland.
As I said the sponge filters work fine in our holding, spawning and rearing tanks. They look a bit ugly, so you probably wouldn't use them in a display tank.
One thing. You MUST do regular water changes and clean the sponge often. We just give each sponge a squeeze or two to get rid of most of the muck, then put it back in. That way you don't upset the biological function, but get rid of the spam that accumula
tes on the outside. Perhaps this list needs a sponge filter.
If you don't have an abundant supply of cheap water you might need to consider a recirculating system, or treating your waste water before reusing it.
Cheers.
Rob Wager
Freshwater Fish Biologist
Raintree Aquatics Pty Ltd
Aquatic Environment, Fish and Aquaculture Specialists
1002 Caboolture River Road, Rocksberg, Queensland, Australia, 4510.
Phone 07 5496 7939, Facsimile 07 5497 0022, International +61 7 5496 7939
Email raintree at closer.brisnet.org.au