Koi Care Basics Blog

Which Koi pond liners  are better;  rubber liners or a concrete pond?  Both have advantages and disadvantages.

When a concrete pond is designed and built correctly it can be more permanent. You need to be very careful when designing a concrete pond that you have planned everything properly because once installed it literally is “cast in stone”!

You can form the shape and contours so that they are very smooth and even which is a must to avoid “dead areas” in your Koi pond.

The biggest disadvantage with concrete pond is that because of all the exposed concrete the ph tends to be higher for at least the first three years. There are, however, things that can be done to prevent this.

One way is to let the concrete cure and then coat it with a rubber base paint or epoxy.

A 45 mil rubber liner pond  is not as permanent. Rubber liners also come in a variety of thicknesses, with the thicker liners being more durable but the thinner ones being easier to shape and mold.

This lack of permanence can be a benefit in some situations. If your pond ends up having some design flaws that need changing, or if you need to move or remove the pond, you’ll be glad you’ve chosen a rubber liner.

An additional advantage is that rubber Koi pond liners will maintain a more neutral ph.

Rubber liners also provide a softer surface for your Koi.

A disadvantage of rubber Koi pond liners is that even when the liner  is installed properly you will  still  have some minor folds in the liner. Once you fill your pond these folds will barely be visible.

Another challenge with a rubber lined pond is the rock work around the edges.  If you don’t want the liner to show it will be necessary to camouflage it with rock work and plants.

The challenge is that the rock work will need to extend down into the water but the mortar for the rock work won’t stick to the liner.

Even though a rubber liner is less permanent when it is properly installed it can remain leak free for many years.

Taking into account the pros and cons of each will help you to make your own decision about Koi pond liners!

Alan Deacon
KoiCareBasics.com