Buy Bentonite Clay Engineering grade online UK -Sealing ...
Bentonite For Sealing Ponds: Sodium Bentonite clay swells up to eighteen times its dry size when it becomes wet. Expanded bentonite forms an impermeable gel seal which makes an excellent pond sealant. Bentonite is environmentally safe and does not affect the water, livestock, or wildlife. When properly applied, it will not harm fish.