With careful construction techniques and the right choice in liners, you will create a worry-free pond that won’t develop leaks for decades. Should a leak develop, however, it can be much more difficult to diagnose and repair when the wrong type of liner is used. Tearing out the entire pond to replace a faulty liner is difficult, wasteful, and expensive.
Finding and Patching Leaks
Preformed ponds are made of rigid materials that are prone to cracking, especially in cold weather. They also develop small, unnoticeable pinholes in areas where the material is thinnest and weakest with no visible change in the material. Finding the leak can be close to impossible, and if you can’t find it, you can’t fix it. It’s not uncommon for someone to buy another preformed pond to replace the leaky one, only to experience the same problem with the replacement pond.
When leaks occur, the pond may begin to slowly lose water. Unfortunately, because most preformed ponds are small, when a leak occurs, the pond can empty quickly and sometimes even overnight. This spells death for fishes and plants before you even realize there’s a problem.
Once the leak is noticed, there’s not a reliable way to locate the leak when the pond is in the ground. You could remove the liner and test it above ground, but this can potentially damage the preformed liner and weaken its integrity since it requires support when filled. When preformed pond liners have leaks, the typical recommendation is to replace it.
If you manage to locate the leak, you could use a fiberglass patching kit for fiberglass preformed liners or sealants/tapes for plastic preformed liners. Both have problems forming a watertight seal, however, and often fail. Even worse, the chemicals in them release toxins and contaminants into the water, thereby, poisoning the fish.
Though damage to flexible liners is rare, especially when using a quality RPE liner such as AquaArmor, repairs are easily accomplished using heat sealing equipment or adhesives and sheets of material. Fish and plant safe patches are readily available for flexible liners, making patches to flexible liners much safer for fish than preformed pond liners.
Replacing Damaged Liners
When it becomes necessary to replace a liner that has reached the end of its lifespan, there is a major difference between flexible liners vs. preformed pond liners. A large preformed pond liner can be too heavy and cumbersome for one person to lift without equipment; however, a flexible liner is easily cut into small manageable pieces and removed without difficulty. Not only is it more difficult to remove a preformed pond liner, but it’s also required much more frequently. The average lifespan of a preformed pond liner is ten years, whereas a flexible liner will last for decades. In areas where the ground shifts or experiences cold upheavals, the life expectancy of a preformed pond liner is even less.
Conclusion
As you look at the problems caused by leaks and what it takes to repair them, it becomes immediately apparent that flexible liners are much easier to work with. As you consider whether to use a preformed pond liner or a flexible liner, it's important to also consider replacement costs. Although a flexible liner such as AquaArmor may cost more upfront, when you figure the costs associated with the install and removal of several preformed pond liners compared to one install of a reliable, flexible liner over the same period of time, the flexible liner easily becomes the smartest choice.
