Which pump option is best?
When it comes to choosing the right pump for your water garden or koi pond, there are two main types – external and submersible. Depending on your needs and preferences, you can select either an external or submersible pump for your pond. Each type of pump has its own set of advantages and disadvantages that should be taken into consideration when making the decision. In this article, we will discuss the various factors so that you can make an informed decision about which style is best for your application. Please note that we are referring only to pumps designed and manufactured specifically for ponds and water features. Pool pumps or sump pumps that are made for other applications are generally not suitable and the following specifics may not apply.
A submersible pump is designed to be placed directly into the pond water. This will typically be in a skimmer or simply submerged in the pond itself.
An external pond pump is placed outside of the pond and the intake is connected to the pond through piping. This also can be drawing water through a skimmer or the pond bottom as well as other gravity-fed filters such as the Nexus.
When most people are first thinking about a pond pump the default is a submersible pump, but is it the best?
Submersible Pond Pump Pros:
- Usually lower purchase price
- Typically easier to install
Submersible Pond Pump Cons:
- Average life of pump is shorter
- Cost of operation is usually higher (this can vary significantly and a pump to pump comparison would be needed)
- If in the pond bottom, the pump will take up space in the pond and possibly be visible.
Submersible pumps placed in the bottom of the pond will usually just have a section of flexible tubing attached to the pump discharge that carries the water to the waterfall or other decorative feature. The pump can usually be disguised by having surface plants like water lilies growing on the pond surface. Similarly, the submersible pump can be placed inside a pond skimmer with piping attached. This gets the pump out of the pond itself which makes it easier to service and hide. Most ponds use a submersible pump, and it is often a more reasonable choice for small to medium ponds.
External pumps bring new options to the installation details and with it their own pros and cons.
External Pond Pump Pros:
- Usually have a much longer life span
- Cost of operation is often lower (this can vary significantly and a pump to pump comparison would be needed)
- Allows the option of adding other gravity-fed filters
- Allows easier ways to split the intake and draw water from different locations, such as pulling from both a bottom drain as well as a skimmer.
External Pond Pump Cons:
- Usually more expensive purchase price
- Plumbing is more involved and may require special priming
- Needs to be disguised (if desired)
- Sound may heard
The additional expense of the external pumps can usually be gained back relatively quickly both with the cost of operation and the years of service. While the pumps do make a humming sound that can be heard, it is usually not going to be heard above the sound of the waterfall and other ambient noise. However, some of the more powerful high-speed pumps will be noisier and accommodations may need to be considered, such as sound barriers in the way of fencing or other means.
External pumps also need to be primed for operation. This simply means that water needs to be in the piping for it to push water from the pond. If the pump is placed below the water level in the pond with the intake piping also staying below water surface level, then the line should always stay full and the pump primed. If the pump is placed above water level, then manual priming will be needed when the pump is first started up – then a check valve installed on the intake line should hold the prime going forward. Or a self-priming pump can be used which will negate the need of manual priming. These self priming pumps can also be placed further away from the pond intake if needed.
If you don’t want to see the pump, then the external pump will need to be camouflaged or hidden. Note that external pond pumps are weather resistant. They can take rain, snow, etc. However, they cannot take submersion, so care needs to be taken that the pump is placed where standing water could never collect.
As a side-note, if the pond is intended to be used for swimming or wading then the use of an external pump is safer as it gets the electrical component out of the water.When deciding which type of pump is best for your pond, it is important to consider the size of your pond, the volume of water it holds, and the desired water flow rate. When selecting a pond pump, it is important to take this information into consideration. And when selecting the specific pump you will need to look at other pond details, such as pond size and desired flow rate. Doing so will help to ensure that you select the type of pump that is best suited to your pond and its needs.