Preformed pond liners are often touted as the “answer” to many pond installation dilemmas and as an easy and affordable way to build a pond; however, their marketing claims often fall short. In fact, many times, preformed liners are more costly, more difficult to install, less durable, and cannot meet the design specifications for varying pond applications when compared to a flexible liner.
Some of the biggest disadvantages associated with a preformed pond are due to its essential nature – it is pre-formed. Its size is predetermined and pre-set. It cannot be changed or altered, and these constraints can be unforgiving.
Installation requirements also cause some difficulty during the install. The excavation must be more precise -- a couple of inches larger than all pond surfaces. The preformed pond liner is placed in the excavated hole and then sand is backfilled around the liner, providing a cushion between the liner and the ground. Because the liner has shelves and near-vertical walls, it can be difficult to get sand into every crevice to support the entire outer surface of the pond. When the pond is filled with water, the weight of the water causes stress in areas where backfilling has been inadequate, leading to stress cracks and future premature failure.
Depth Disadvantages of Preformed Ponds
Preformed ponds are relatively shallow. Most have, in fact, a maximum depth of 18-24 inches. This is fairly shallow, to begin with, especially for Koi who thrive best in a pond that is at a minimum of three to four feet deep. Then the ponds depth is substantially reduced when you consider any sand, rock, decorative items and the accumulation of natural muck.
Preformed ponds are typically too shallow for most fish species other than small koi (which quickly outgrow a shallow pond) and goldfish. Many plants, such as lotuses, water lilies, and cattails, also require more depth to thrive.
Additionally, shallow bodies of water heat up and cool off quickly causing undue stress on fish. Shallow ponds are often plagued with overgrowth of algae and generally require more maintenance than their deeper counterparts.
Flexible liners, such as those offered by BTL liners, can be installed to virtually any depth, providing design flexibility that encompasses the needs and purposes of any pond.
Size Limitations of Preformed Ponds
Due to their one-piece design, preformed ponds have a limited size range. Larger sizes can be custom ordered; however, size exponentially increases shipping and installation costs. But even at their largest conceivable size, they are impractical for many pond applications.
Contrary to what one may think, smaller bodies of water generally require more maintenance and filtration to maintain water clarity and a stable pond environment.
When using a flexible liner such as AquaArmor, a pond can be created that is any size, shape, depth, and layout you desire. You’re limited only by your imagination. Whether your pond is measured in gallons or acres, BTL Liners offer a flexible liner that meets your design’s specifications.
Layout and Shape Limitations of Preformed Ponds
When using a preformed pond liner, it can be difficult to create a design that blends seamlessly into the landscape, complementing the existing curves and lines of its surrounding features. A flexible liner, however, allows you to design and create a pond that meshes with any existing features of the landscape, creating a much more aesthetic, natural-looking pond.
Preformed ponds are manufactured with a lip that must be installed above the surrounding soil (a couple of inches is recommended), making it difficult to conceal. Because large stones or mounds of gravel are often used to secure and conceal this lip, the installation has an unnatural appearance. Additionally, since the lip is only a few inches wide, fastening it securely can be problematic. The lip is inclined to work free from the materials intended to secure and conceal it. Frost heaving often causes the lip’s edges to work loose and protrude, as well, causing it to become more visible each year.
Flexible liners, on the other hand, conform to the existing landscape. Its edges are easily covered with soil or gravel which merges naturally into the surrounding landscape and creates a natural transition between water and the adjacent area.
Preformed liners aren’t typically designed for the addition of waterfalls and fountains. When these features are installed, the resulting splashes and small waves often cause surrounding soil to become waterlogged, leading to collapse into the pond. Flexible liners, on the other hand, are easily extended to encompass whatever area is required to protect the embankment from splashing and erosion.
With a preformed pond whose edges must be covered with rock slabs or gravel, adding a bank is not an option; whereas, a flexible liner makes it easy to create a natural-looking bank while also protecting the soil so it will remain in place for many years to come.
Conclusion of Size, Shape, and Depth Issues
Flexible liners, like AquaArmor from BTL Liners, give you the freedom to design and install a natural-looking pond that blends into the existing landscape. Flexible liners also enable you to create the bank style of your choosing, implement as many planting shelves and ledges as you desire, add gentle contoured slopes to your pond’s bottom, and add overhangs to provide the perfect place for fish to spawn or hide.
