Concrete is a great pond-building material as well as bricks. But both type of pond needs to be waterproofed before you stock it with fish. It can be done by using liner, paint, or other sealants.
In this article, I will talk about the two best pond sealers and paint that you can use to waterproof your Koi pond.
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Our Recommended Pond Sealer And Paint
What Type of Paint or Sealer is Used for Waterproofing Pond
Although there are many ways to seal a pond, Epoxy paint, and Liquid Rubber paint are the most widely used. You can also use other water-based waterproofing paint for this purpose. But these two work best.
Epoxy paint is the first choice of pond owners and there are good reasons behind that. It consists of a base as a curing agent. After you have finished painting your concrete pond, it will give you a durable waterproof surface.
The reason is Epoxy is resistant to chemical agents which makes it last longer. Another good side of Epoxy Paint is it is entirely safe for fish, pond plants, and any other animal.
Epoxy paint is brittle. Hence if the concrete has a micro-crack and any settlement occurs after the painting is done, it will break in that place.
The downside of epoxy is it is more expensive than other paints. But being nontoxic it is still the first choice when it comes to painting a concrete pond.
As a substitute for Epoxy Paint, you can use Liquid Rubber paint. It is cheaper than Epoxy and can give almost the same performance.
After application when it is cured, it forms a waterproof membrane. Being flexible it will not damage easily. Also, rubber paint doesn’t contain any volatile material and is non-toxic to fish and other animals. You can use this one when you want to save some bucks.
Best Pond Paint: Pond Armor SKU-BLACK-QT-R Non-Toxic Pond Shield Epoxy Paint
The Pond Armor SKU-BLACK-QT-R (link to amazon) is the best epoxy pond paint widely used for sealing concrete ponds. It works on various types of surfaces like brick, stone, and concrete.
The best thing about this pond paint is it doesn’t require any primer like rubber paint and it only requires 24 hours to cure. It gives a very smooth surface. Therefore, there will be less algae growth in it and cleaning is very easy.
Also, Pond Shield made this Epoxy paint flexible, not brittle. Hence, it will not crack with the concrete and hold water well.
It is safe for fish, plants, and other animals. You can also use it for a turtle pond and birdbath. It also has great temperature resistance. It can prevent the freeze and thaw action due to temperature change and hence lasts longer.
The coverage of this epoxy paint is awesome. The pack of 1.5 quarts will cover 60 square feet in one coat. It is available in 8 different colors.
Best Pond Sealer: Liquid Rubber Waterproof Sealant
Liquid Rubber Waterproof Sealant (link to amazon) is the best concrete pond sealer. It is a water-based liquid rubber sealant that is safe for both fish and the environment. It is free from any solvent and also VOC-free. It works on various types of surface and concrete.
After application, it will form a membrane that is fully waterproof and gives a pleasing appearance. In the bottom, you should apply 3-4 coats at the bottom and 2-3 coats at the side.
The coverage of this sealant is good. It gives 50 square feet per gallon for the flat surface and 100 square feet per gallon for the vertical surface. Use a paintbrush or roller to apply this sealant. Use 2 coats of primer before you apply this one.
This liquid rubber sealant should be applied in a completely dry condition. The surface should be free from dust, grease, oil, and paint. While using the surface temperature shouldn’t be less than 5 degrees Celcius.
It will take one to two days to cure. And after that, it will fully hold the water in your pond.
Why You Should Seal Or Paint Your Concrete Pond
The first reason why we paint or seal our concrete pond is to stop lime leaching. Concrete contains a large amount of lime. Not all the lime is used when the concrete sets because it is a never-ending process. The hydration and setting of concrete go forever. If you add water to a newly constructed concrete pond, you will see thing layer of lime over it after 24 hours.
Now, this extra amount of lime can leach and mix with pond water. Lime in water is harmful to fish. So to stop lime leaching, we should seal the concrete pond.
Another reason to seal a concrete pond is to save the reinforcement that is within the concrete. If the concrete is highly damp with water, the reinforcement will get corrosion soo. The result will be a large crack in the pond and water loss.
Although concrete can resist water to some degree, if there is a constant water load on concrete, the water can percolate through it. This causes water loss in the pond and also makes the outside of the pond damp. And if the pond is above the ground, there will surely be algae and moss growth which will make it unpleasing.
The final reason to paint a concrete pond is to give it a pleasing appearance. An unpainted concrete pond doesn’t look good as the color of the concrete is not black. Most of the pond owner wants their pond to be black because a pond with a black bottom looks the best.
Epoxy Paint or Rubber Sealant – Which One To Choose For Your Pond
If you have a smooth concrete pond and no problem with the budget, you should go for epoxy paint. Epoxy paint makes it easier to clean the pond and prevents algae growth on the side as it is very smooth. It also takes very little time to cure. Again there is no need to apply any primer if you use it.
Liquid rubber is recommended when you have a rough finish in your pond, like an unfinished brick pond. It also saves you some bucks when it comes to coverage per gallon. But it takes a longer time to cure than the epoxy. Again algae growth is more than the epoxy as the surface isn’t smooth.
Whatever paint of sealer you choose for your pond, make sure it is safe for fish and pond plants. Also, make sure it is durable because you don’t want to paint your pond every year.