The Pool Mate forest green Above-Ground pool cover protects your pool during harsh winter conditions. This professional-quality, polyethylene cover blocks out any dirt and debris throughout the winter. The forest green cover prevents algae growth by blocking UV rays from entering your pool. Pool owners who use a Pool Mate forest green pool cover and close their pool with the proper winterizing chemicals will have a clean pool in the spring that will be easy to open. It is always recommended to o.