Cycling question...

[Richer]

Originally Posted by Marnie

Can I use a seeded sponge filter from a freshwater tank for a saltwater QT tank??

As far as I know... it cannot be done. Most freshwater organisms will literally shrivel up if you stick them into saltwater. In the opposite situation, most SW rganisms will either swell or burst if placed in a FW situation for an extended period of time. This gets worse if you get into relatively simple organisms. For example. freshwater fish constantly try remove water from their bodies and saltwater fish are constantly "drinking" water. You can imagine what will happen if they're placed in opposite situations (assuming they survive long enough in the first place). Of course, bacteria continue to defy the "laws" of nature and new things are always being discovered... but as far as I know the bacteria that we use in our aquariums do indeed follow this general rule of thumb.

-Richer