Soil type and pond size are the key factors in determining the amount of sodium bentonite required to seal ponds. Normally, coarse soils require more bentonite. If the size of pond is known and the type of soil is available, the chart above gives a good estimate on the amount of bentonite needed to seal pond. The chart at left is based on water depths of up to eight (8) feet.
For depths greater than 8 feet: Since greater water depths increase the pressure on the bottom of the pond, increase the application rate listed in the chart above by one pound per square foot for every 8 feet of additional water depth. For example, add one pound per square foot to the "Application Rate" for depths of 8' to 16'. Add two pounds per square foot to the "Application Rate" for depths of 17' to 24', and so on. Performing a SOIL TEST is another good way to estimate. You can perform the soil test yourself or contact your local conservation service for a free test.
APPLICATION METHODS (Click on the method below for details)