Shop for Cleaning and Maintenance from Hayneedle.com! Easy to use, the Nava Chlorinating Shock - 1 lbs kills algae and removes unsightly spots from your pool. Ideal for vinyl lined and fiberglass pools. No pre mixing required.About RobelleKnown as a leader in the pool industry, Robelle has been a top supplier of products, chemicals, and accessories since 1973. Their products reflect the high quality standards and practices the company subscribes to and is dedicated to offering customers the best possible products available for keeping pools clean and maintained properly. Robelle has been supplying swimming pool chemicals and accessories to regional and national chains, as well as New England pool specialty dealers for over four decades and continues to grow a dedicated clientele of satisfied pool owners.