Pond Bentonite Clay Sealer Calculator
Calculate bentonite clay sealer pounds for a leaking pond from surface area and the application rate per square foot, with total tons.
How This Calculation Works
Bentonite pounds equals the pond surface area in square feet times the application rate, typically 1 to 3 pounds per square foot depending on soil permeability. Surface area is length times width. Dividing by 2,000 gives tons for ordering.
Field Calibration & Rate Reference Chart
| Surface ac | Avg depth | Acre-feet | Copper lb @ 1 ppm |
|---|---|---|---|
| 0.25 | 4 ft | 1.0 | 2.7 |
| 0.5 | 4 ft | 2.0 | 5.4 |
| 0.5 | 6 ft | 3.0 | 8.2 |
| 1.0 | 4 ft | 4.0 | 10.9 |
| 1.0 | 6 ft | 6.0 | 16.3 |
| 1.5 | 5 ft | 7.5 | 20.4 |
| 2.0 | 5 ft | 10.0 | 27.2 |
| 2.0 | 8 ft | 16.0 | 43.5 |
| 3.0 | 6 ft | 18.0 | 49.0 |
| 5.0 | 6 ft | 30.0 | 81.6 |
Common Questions
How much bentonite do I need to seal a pond?
Apply 1 to 3 pounds per square foot of pond bottom, with higher rates on sandy or gravelly soils. A 6,000 square foot pond at 2 pounds per square foot needs 12,000 pounds, or 6 tons. Mix it into the top few inches.
Does bentonite work on all soils?
It works best on sandy or gravelly soils where the clay can swell into the pore spaces. On rocky or highly permeable sites it may not seal reliably, and a synthetic liner is a better choice. Test a small area first.
How do I apply bentonite to a pond?
Spread the powder evenly over the dry pond bottom, mix it into the top 4 to 6 inches of soil, and compact it. Then fill slowly so the clay hydrates and swells. Apply in calm weather to avoid wind loss.
How long does a bentonite seal last?
A properly installed bentonite seal can last many years, but it can fail if the clay dries and cracks or if the water level drops repeatedly. Keeping the pond full helps maintain the seal. Reapply if leaks return.