Reef Endurance GFO 4.5lbs Phosphate Adsorption Media is a high-performance granular ferric oxide filter media designed for both fresh and marine aquariums. This powerful media effectively filters out phosphate from the water column, a critical step in maintaining a thriving reef environment. By diligently removing phosphates, it actively helps prevent unsightly algae outbreaks and fosters superior coral growth and coloration. Featuring a porous, high surface area design, Reef Endurance GFO is highly efficient at binding not only phosphate, but also silicate, arsenic, and other compounds that can stain your aquarium water. For optimal results, utilize this media in an up-flow media reactor with a flow rate of approximately 100 gallons per hour. It can also be passively used in a fine filter bag or media basket. Remember to thoroughly rinse the media before use until the water runs clear, and replace it every 4-6 weeks or when phosphate levels begin to rise. This phosphate adsorption media is an essential tool for any serious reef aquarist aiming for pristine water quality and vibrant coral health. It is ideal for those struggling with nuisance algae or seeking to maximize the growth and vitality of their corals by maintaining ultra-low phosphate levels. Whether you are a seasoned hobbyist or just starting, Reef Endurance GFO provides a reliable and effective solution for a healthier, clearer, and more beautiful saltwater aquarium.