Thank you for your questions. UV Sterilizers will not remove hair algae in your pond, but it does help to clear free-floating algae that cause the water to turn green. The algae you are experiencing in your pond is most likely due to excess nutrients, silicates, and phosphates in the water. You are able to control the growth of the algae by cutting back on feeding the pond to once every other day, and by adding a phosphate remover or absorber to the filter system. Adding plants to your pond will eliminate the excess nutrients and silicates in the water that the algae needs to grow. It will also shade the pond, which prevents the amount of direct sunlight that algae use. You are able to take a very soft bristled brush and scrape the algae from the rock and liner of the pond right away. Be sure to siphon any algae from the water to prevent any additional waste, as the algae will decay in the pond causing high phosphates and additional algae growth.