Do I need carbon in my aquarium filter?

Because activated carbon (and most chemical filtration) is disposable and cannot be reused, we like to save it for specific instances when we know there are pollutants or tannins that we wish to remove. If you are preparing for an aquarium photoshoot, you may choose to use carbon to ensure the water is extremely clear. However, most hobbyists do not use carbon on a daily basis because it gets depleted so quickly and the results may be temporary.

For more information on filter media, read the full article here.