API BIO-CHEM STARS are an aquarium filtration media that start the biological filter and work to establish and maintain a healthy eco-system. BIO-CHEM STARS use a 50-70 micron internal pore network to promote the growth of beneficial bacteria in fresh, saltwater, and reef aquariums, inluding nitrifying bacteria that remove toxic ammonia and nitrite. It also allows the best oxygen and water transfer through the star, which keeps bacterial colonies healthy and active. Use to start or maintain a healthy aquarium. Contains 20 stars and treats up to 100 US gallons of aquarium water. Use according to directions on product packaging. With API Aquarium products, it’s easy to keep a beautiful saltwater, freshwater or reef aquarium. For over 50 years, API has been creating innovative, research-driven solutions that make it easier to care for your fish and aquarium. API Aquarium Treatment Supplies are designed to work in conjunction with each other to provide best results to control algae, promote healthy bacterial growth and help control and cure fish diseases and conditions such as ich and fin rot. They work to provide a safe, hospitable environment for fish such as tropical community fish, cichlids, goldfish and more. With API, you can spend more time admiring your fish, and less time scrubbing your tank. Make sure to use all products as directed in order to ensure the best results. GTIN:00017163017318. Free Shipping in the USA!