Bentonite pond sealer, a natural clay product, chemically attracts to itself and swells up to 12 times its dry size when moistened. It also makes an excellent liner for new pond construction. It can help your pond to retain its water levels and reduce the rate of water seepage significantly. They are processed to hold water and make surface to zero seepage. It does not contaminate the water. It has the property of quick adsorption. It is a cost-efficient pond sealing element.