The AquaMiracle Aquarium Filter is designed specifically for green water problems in fish tanks ranging from 10 to 40 gallons. This U-shaped filter utilizes a unique time-dependent cleaning system to effectively combat algae growth and keep your aquarium water clear and healthy for your fish. The AquaMiracle brand is known for producing high-quality aquarium products, making it a reliable choice for maintaining a clean and thriving aquatic environment.