When you are setting up your pond, one of the first things you’ll have to think about is your pump. What is the best kind? What size do you need to accommodate your pond? These questions and more will be running through your mind, so it’s a pretty good idea to do a bit of homework before you get started.
The first thing you’ll have to decide upon is out of all the pond pumps available, do you want an external or submersible . Submersible pumps obviously run entirely under water and often have a water pump connected to the housing, which aids in installation. Most have attractive fountainheads that help keep the water aerated, and some more expensive models even come with UV sterilization built-in. A big advantage of a submersible pump is the fact that it’s completely hidden under the water. Generally, submersible pumps are ideal for ponds under 2,000 gallons, easy to install (as there is no external plumbing), and considered more economical for the smaller pond owner.
External pumps go above ground, near the pond. External pumps are easy to access for maintenance and are great for ponds over 2000 gallons. Two common drawbacks to external pumps are that they can be noisy, require a bit of plumbing, and can be hard to hide. If aesthetic appeal is important to you, you can always build an attractive housing for the pump.
What about size? It’s very important that you have a pump that meets the requirements of your filter and the size of your pond. Many water garden stores will have charts or helpful employees that can point you in the right direction, but there are a few common ideals that you’ll need to meet.
First, get to know what size pump you need for your pond. Your average backyard pond pump will be sized by how many gallons per hour (GPH) it puts out at 1’ of height or lift. No matter the manufacturer, you should be able to find a chart that shows the power of all the pumps in terms of incremental heights of 1’. Essentially, what you are looking for is to have all the water in your pond be turned every 1-2 hours. Therefore, if you have a 1,000-gallon pond, you need at least a 1,000 Gallon per Hour (GPH) pump. You also need to consider how high the pump will have to lift water, and whether or not there will be other things that may obstruct flow or water clarity, such as statuary, waterfalls, or filtration. In general, if you have a choice always buy a pump that can handle what you need, and then some. The pump you buy will never be able to handle more than what it has been manufactured to, so it is always better to be safe than sorry.
Next, and this goes hand-in-hand with the first point, you have to determine the size of your pond. First, you’ll have to estimate the distance from the top of the pump to the top of the stream or waterfall and add another foot of lift or height for every 10’ of hosing you need. This allows for a loss of volume from resistance gained by passing through the hosing. Usually, your waterfall/stream requirement will be 150 GPH per inch of width of the channel. So if your waterfall or stream channel is 15” wide, you need a pump that produces a flow of 2250 GPH (15” x 150 GPH = 2250 GPH). Of course, you’ll have to add in the variables mentioned before (distance between pump and stream, hose length) as well.
All these details may sound daunting, but if you go to the right dealer, they will be able to help you. Just have your measurements in hand and they will be able to point you in the direction of the pump you need!