Can I be filled in on filters?

[VioletThePurple]

What is filter media? Is it the sponge part of the filter? Inside my filter is a piece to hold the bag, that has a sponge. The bag itself is really gross looking, even after cleaning so I guess that's just normal. It has little pieces of coal in it. My filter is a regular, hang on the back. I keep hearing about filter media and filters with carbon but I don't really understand. Can someone fill me in?

 

[Oblio]

Media is the stuff that is in the filter housing that the water flows through. They are used to perform different functions: Mechanical filters out gunk, biological houses bacteria, and chemical removes medication or alters tank chemistry.

Examples (with function)
Sponge - Mechanical, Biological
Floss or poly-batting- Mechanical
Ceramic rings - Biological
Charcoal - Chemical
Resin - Chemical

Generally you do not need charcoal or resin. I would also avoid replaceable cartridges and change to washable sponges. I use a combination (in order of water flow) of Sponge (prefilter and main), poly-batting, ceramic rings in my HOB.