Why do fish tank filters have charcoal in?

* Removes organic toxins: Activated charcoal is a highly porous material that has a large surface area, making it an effective adsorbent for organic toxins. These toxins can come from a variety of sources, including fish waste, uneaten food, and decaying plant matter. Activated charcoal can help to remove these toxins from the water, preventing them from harming fish.

* Dechlorinates water: Chlorine is a common disinfectant that is added to tap water to kill bacteria. However, chlorine can also be harmful to fish, as it can cause gill damage and other health problems. Activated charcoal can help to remove chlorine from the water, making it safe for fish.

* Removes heavy metals: Heavy metals, such as lead, copper, and mercury, can be toxic to fish. Activated charcoal can help to remove these metals from the water, preventing them from harming fish.

* Improves water clarity: Activated charcoal can help to improve water clarity by removing particles that can cause the water to appear cloudy or murky. This can make the tank more visually appealing and easier to see the fish.

* Provides a surface for beneficial bacteria to grow: Activated charcoal can provide a surface for beneficial bacteria to grow, which can help to improve water quality. These bacteria can help to break down organic matter and convert it into harmless substances, such as nitrates and nitrites.