The AquaReady Hang-On-Back Refugium is a tank-mounted refugium designed to enhance the water quality of saltwater aquariums by providing an environment for macroalgae growth. This device helps in controlling nitrates and phosphates, which are key nutrients that contribute to nuisance algae blooms within the main display tank. By growing beneficial macroalgae in this separate compartment, it also competes with unwanted algae while offering a refuge where microfauna such as copepods can thrive. The AquaReady Hang-On-Back Refugium is suitable for aquariums 20 gallons and larger, requiring a minimum length of 17 inches and glass/rim thickness up to 0.75 inches. It comes with a standard one-year warranty from the manufacturer, ensuring durability and reliability in your reef ecosystem.