Sponge Filter

[Missy]

Can someone explain how a sponge filter works. From what I can tell it uses an airpump and basically, a sponge . I don't get how anything is sucked into anything and what it keeps clean in a baby tank for example. I doesn't collect junk the way a power filter does, or does it. I'm confused. A little embarassed too )

 

[Alien Anna]

Most of them work by driving air through a thin pipe. Then, as the air tries to escape it drags water with it. The only way the water can get in is via the sponge over the opening. After it's travelled through the sponge and into the pipe, the water pours out of the top as the bubbles of air escape. It's physics!