Bentonite Pond Sealer is cost effective, non toxic and a long lasting solution for sealing ponds and lakes

How does bentonite pond sealer work?

Sand, rocky ground, rock formations and gravel leave small cracks and holes through which the water slowly seeps. Sodium Bentonite Pond Sealer is your best ally to solve the water loss problems. Bentonite will find its way inside those small holes and cracks of the soil, and then it will swell at the contact with water, thus creating a seal that will prevent water seepage, making it a great pond sealer and liner.

Bentonite is a mineral clay, milled to specific standards, that will blend seamlessly into the nature of your pond. It is free of chemical additions or hazardous materials and non toxic, therefore you can safely hold it in your hands with no harm. Use it for fish, duck, or wildlife ponds. It is especially ideal for stock and farm ponds because it won’t be damaged by the steps and weight of the stock or other animals.

Bentonite Sealer is easy to apply in either dry or wet ponds (ponds that can’t be drained), is a 100% natural earth sealer, and is safe for fish, safe for plants, safe for stock, and safe for swimming. It is cost effective, as it is comparable in price to other similar sealing products and, when applied correctly, it will create a seal that will last for a long time.

You can use our Bentonite Calculator at the bottom of this page to obtain a better approximation of the amount of bentonite you require to seal your pond.

Bentonite Pond Sealer Application

Bentonite Clay Pond Sealer Application in a Retention Pond

Application is key for success. We can’t stress enough the importance of the correct product application. It is the difference between a full pond for years to come or headaches year after year.

It’s not uncommon for customers to call in because they have a leak in the dam area. In those cases, we use a method called the sprinkle method, where the bentonite pond sealer is applied over the water surface. We use this method for ponds that can’t be drained. The sealer will start to sink to the bottom, following the flow or current created by the leak through the water. It can be done for the whole pond, or only for a problematic area, in which case it is called spot treatment. Spot treatment is a variant of the sprinkle method, where the sealant is applied only to a particular area of the pond.

When there isn’t a single identified area for the pond leaks, we recommend drying the pond, when possible. For dry ponds, there are 2 methods. The first one is the blanket method, which requires removing debris to create a surface as smooth as possible, removing about 6 inches of soil, applying the amount of sealant required in an even layer and then covering the layer of sealant with the soil that was previously removed. Then it is ready to slowly add the water in.

The mixed blanket method requires to rake or till 6 inches of soil and then apply the sealant as if you were seeding or fertilizing. Rake again to mix the bentonite into the ground and compact the ground. Remember to add the water in a steady flow to prevent disturbing the layer of product you just created.

It is highly recommended to have a professional service for sealing a leaky pond or stop water seepage. If you require a turnkey service that can take care of diagnosing, sourcing and applying the materials to repair the pond, visit our Pond Repair Service page.

Benefits of using sodium bentonite clay as a pond sealer

Bentonite vs Soilfloc

There are 2 categories of pond sealer products: active and passive. Bentonite is an active pond sealer, which means it interacts with the environment to create a watertight seal that prevents leakage. In the same category, we find polymeric pond sealants like Soilfloc, which makes them our best competition (yes, we respect them and we’re not afraid to talk about them).

Let’s start by explaining how polymeric sealant products work. The polymer molecule (which is called anionic polyacrylamide) is a man-made product that, as its name says, has negatively charged ions, giving the polymers ability to attract positively charged clay cations. So yes, they actually attract the existing clay in your pond for the sealing process! In combination with a man-made polymer. What do we think? Well, we think that if the clay alone can work for you, why use a man-made product? Of course, this depends on each particular case and while bentonite sealer might be best for some cases, soilfloc can beat us in other cases. It all depends on the customers project.

Polymer products usually come in parts, a format that requires you to apply part A and then, part B. With bentonite, you have a single application and that’s it. No parts, no complication.

Is there a better product choice between polymer sealants like soilfloc and bentonite pond sealer? We believe there is, but it will depend on your particular project needs and your personal interests. While polymer products may be required in some cases, if you are hesitant between these 2 types of pond sealer products give us a call. We will honestly tell you if bentonite is not the best choice for your project (yes, integrity is one of our core values).

What are the benefits of using bentonite as a pond sealer?

Sealing leaks or full ponds with bentonite is cost effective, non toxic, environmentally friendly and long lasting. It is quite easy to apply, although it is important to get it right in order for the seal to be effective.

How much sealant is needed for a 1 acre pond?

The short answer is between 30 and 80 tons of bentonite, to line the whole pond.
The most important factor to determine the amount of bentonite pond sealer required is the type of soil of your pond. Depending on it is how much bentonite pond sealant we recommend applying per square foot.

How much bentonite is needed to seal a pond?

The short answer is between 30 and 80 tons of bentonite, to line the whole pond. That said, this is based on a pond that has measurements of 208 feet x 208 feet and 8 feet depth. It is quite a large pond, and the exact amount of sealant will depend on the type of soil of the pond bottom the more porous it is, the more product will be required to create and effective and long lasting seal. The pond sealer itself it’s an inexpensive material, so don’t be afraid to Request a Quote.

Here are some reference values that can help you estimate the required amount of bentonite to seal any area (based on the Lonestar Minerals quality bentonite mix-mesh for ponds). Or, if you prefer, we have available a Bentonite calculator to easily approximate the amount of bentonite required for your pond.

Soil condition → Pond sealant per sqft
Rock or gravel → 3.0 to 3.5 lbs/sqft
Clean Sand → 2.5 to 3.5 lbs/sqft
Silty Sand → 2.0 to 2.5 lbs/sqft
Sandy Silt 20% Clay Min → 1.5 to 2.0 lbs/sqft
Clay Soil → 1.0 to 1.5 lbs/sqft