Activated Carbon (Charcoal) in Aquariums: What It Does, When to Use It, and Common Myths

Activated carbon (often called “charcoal”) is one of the most common aquarium filter media, but what does it actually do, and do you really need it running all the time? In this episode of The Aquarist’s Edge, Art breaks down how activated carbon works, what it removes, what it doesn’t remove, and the best times to use it in a freshwater aquarium. You’ll also learn why pet shops sell carbon so aggressively and how to avoid the cartridge-replacement trap that can destabilise your filter.