What Is Sodium Bentonite And How Does It Work?
Sodium bentonite products are used to seal large ponds, such as man-made fish ponds. The sodium bentonite clay properties are what make the material work so well as a sealant. Sodium bentonite swells to as much as eighteen times its normal size when wet. As it swells, it fills in the holes of a porous material, thus creating a watertight seal.
Sodium bentonite is so effective for this purpose that it has a wide range of uses. Not only do you find people sealing ponds with sodium bentonite clay, but you will also see bentonite clay use for construction waterproofing. Landfills, sewer drains, and similar installations are sealed using bentonite products.
How Does Bentonite Work?
Sodium bentonite is used as a sealant when ponds are leaking. The application can be done through “blanketing” the soil beneath the pond with the product. This has to be done before the pond is filled. The sodium bentonite prevents water loss as the pond ages (and a normal liner can be placed above it.) When applied to a sufficient depth, however, the bentonite itself acts as a sufficiently strong seal to stop leakage through to the soil.
If you have an existing pond that is leaking, you can use the blanket method, provided you drain the pond first. If you cannot drain the pond, the sprinkle method is your best option. Simply sprinkle granular bentonite on the water’s surface. The particles will sink to the bottom where they will saturate the porous places.
Pros and Cons of Sodium Bentonite Clay
Sodium bentonite clay has a number of attract properties as a sealant:
- Its ability to swell and block moisture allows it to seep into the soil at the base of a pond in construction or to patch a pond that is leaking.
- When applied at a thickness of up to 4″, sodium bentonite produces a seal that will withstand use by animals.
- Sodium bentonite is much more affordable than sealing options. (It does, however, have to be applied by a professional.)
One downside to using sodium bentonite clay is that for proper installation, the pond must be drained. If you have fish, this is easier said than done. While you can use the sprinkle method and not drain the pond, this type of application is not fool proof. There is a chance that the clay particles will not reach all of the places in the soil that may be allowing leaks through.
If you want a good pond seal with sodium bentonite, you will need to have a professional apply the materials for the best results. This method is, however, the best way of sealing ponds, when you can afford to do it. Sealing ponds with sodium bentonite clay will create a watertight seal that stands up to years of use.