It’s easy to assume that the rigid materials used for most preformed pond liners makes them more durable than flexible liners. Don’t fall for this misconception. Thickness and stiffness should not be the only considerations when choosing a pond liner. The precise material used for your pond liner plays a large role in its safety for irrigation, fish, plants, or other uses. Fish are particularly sensitive to chemicals that can be used to keep liner materials flexible and resistant to UV damage. This can be a problem with both flexible and rigid preformed liners. Make sure the liner you’re choosing is made from the right material for the job with these tips.
Fish Safety
Almost all preformed pond liners are marketed as being safe for fish. However, few manufacturers of both fiberglass and plastic models follow up this claim with proper testing. In order to verify a pond liner is as safe as it claims, look for certification from the NSF. NSF certified pond liners are tested thoroughly to ensure there’s no chemical leeching that could affect the health of the fish. It’s also possible for find liners rated by the NSF for potable water use and these liners will be safe for both plants and fish. BTL Liners can help you understand fish safe liners more thoroughly and specifically fabricates their industry leading AquaArmor product line for fish and potable water safety.
Weight and Size
One of the biggest problems with preformed liners, especially larger ones, is how unwieldy the liner becomes to handle and transport. The thick and rigid material is less durable and also heavier than thinner layers of flexible liner. There’s also no way to fold or pack away the rigid liner like there is with the flexible material. If you’re ordering a custom design that requires shipping from a distant manufacturer, you’ll pay a premium just to get the preformed liner to your selected site.
Durability
Ignore the common misconception that preformed pond liners are somehow stronger than flexible liners. Despite being flexible enough to bend into practically any configuration, most flexible liners are far tougher than the preformed options and last longer when properly installed. The thickness and stiffness of the rigid liner also causes it to become damaged more easily than flexible materials, especially in cold climates where an entire small pond may freeze to solid ice. Freezing, that occurs under the pond, also leads to cracks that are hard to repair or patch. Even dragging the flexible liner over the ground won’t cause tears or holes when you choose a reinforced liner from BTL Liners.
Cost
It’s also incorrect that buying a small pond liner from a local hardware store will cost less than ordering a section of flexible material. It’s true that you can find tiny preformed liners of 100 gallons or less for under $200. However, a similar section of flexible liner often costs less than that when ordered from a reliable supplier. HDPE, in particular, is highly affordable when ordered in small or large sections. Don’t forget to figure in the cost of extra materials for disguising the edge of the pond. The rock slabs and crushed stone required for edging a preformed liner can easily double the cost of installing the pond. Choosing a flexible liner allows you to get creative with bank protection and may require nothing more than existing soil or sand for the transitional area.
Rigid Liner Options
Most rigid liners are made either from high density polyethylene (HDPE) or fiberglass and resin. Both are available in fish-safe formulations, but HDPE typically offers better fish compatibility. Despite being made from some of the same raw material as flexible liners, HDPE preformed liners don’t offer the same benefits. The rigidity makes them weaker than multi layered RPE liners that contain HDPE. These rigid HDPE liners are often not as affordable as fiberglass shells. PVC preformed rigid liners are also available. This material is the option most likely to contain plasticizers that aren’t safe for fish. It’s also the most susceptible to freezing damage, tree roots, and UV degradation wherever the liner is exposed.
Despite being made of some of the same material as flexible liners, preformed liners never offer the same kind of benefits. You have far more material choices when shopping for flexible products, with the option of multi-layered RPE liners that take advantage of each materials strengths to create the perfect combination of superior freeze resistance, fish safe formulations, UV and tear resistance. Don’t forget to check exactly what material you’re purchasing when ordering a liner, regardless of whether it’s flexible or rigid.
