Tetra Whisper Replacement Carbon Aquarium Filter Cartridges Lg 3-ct. Tetra is a name you can trust in the aquatics industry. With decades of proven performance and high quality products its no wonder Tetra is the go to brand for aquatics beginners and veterans alike. The Tetra Large Carbon Filter Replacement Cartridges promote healthier fish by helping to remove discoloration odor toxins and other impurities from aquarium water. These replacement carbon filters keep your Tetra Power filter running like new. A course later of floss removes larger debris while activated carbons are hard at work to remove odor and discoloration from the water. The set includes three ready to use filters.