Specially formulated Penn-Plax Pro Carb helps to keep your aquarium clean and healthy. Made with laboratory quality activated carbon , this aquarium water treatment removes harmful ammonia, toxins, and odors from your tank. Pro Carb will also help to maximize your filter’s efficiency by helping to keep the water clean. Stop cloudy water from occurring in your tank and keep it crystal clear by adding Pro Carb to your aquarium filter. This special aquarium ammonia remover is safe for both fresh and saltwater tanks. 17 oz.