| The pond pump is truly the "heart" of your pond. | | | | shaft and impeller (the only moving parts). The |
| They are needed for a variety of functions - | | | | downsides are they cannot provide sufficient |
| from general circulation to powering water | | | | water flow for high head applications, and they |
| features. The good news is there are a wide | | | | are slightly more expensive than direct drive pond |
| variety of pond pumps available from very | | | | pumps. In general, if you do not have a high head |
| reputable manufacturers. For just about any use, | | | | requirement and are looking for a submersible |
| there will be multiple products available to choose | | | | pump, the magnetic drive pond pump is the best |
| from. The bad news is selecting the right pump | | | | choice. |
| for your needs can be a very daunting task. In | | | | Air Pumps: Air Pond Pumps do not provide any |
| this article we will provide you with a solid | | | | water flow. They draw air into the pump then |
| foundation to select the right pump for your pond | | | | diffuse it into small bubbles. Air pumps are most |
| application. | | | | commonly used for pond winterization as they |
| Types of Pond Pumps | | | | provide oxygenation and gas exchange without |
| Submersible Pumps: Submersible Pond Pumps are | | | | providing water flow. |
| installed completely underwater, typically in the | | | | Choosing the Right Size Pond Pump |
| deepest part of the pond. This class of pump is | | | | To choose the right size pond pump, first |
| generally suited for smaller ponds, or for water | | | | determine the proper application category: 1) |
| features requiring less that 4,000 GPH. The main | | | | Filtration and Recirculation; or 2) Water Features. |
| benefit of a submersible pumps is that they are | | | | Filtration and Recirculation: The general rule of |
| visually unobtrusive and run very quietly. They are | | | | thumb for filtration and recirculation applications is |
| also very easy to install, just make sure the cord | | | | the pump should turn the pond water over a |
| length is sufficient for your needs. The downsides | | | | minimum of once every two hours, and ideally |
| to a submersible pond pump is that they must be | | | | once an hour. For example, if your pond is 3,000 |
| frequently removed from the pond for cleaning | | | | gallons the ideal pump size is 3,000 GPH, but not |
| and maintenance. They also generally cost more | | | | less than 1,500 GPH. My personal preference is to |
| to operate than an external pond pump, although | | | | always err on the high end of the range. A |
| there have been some significant improvements | | | | pump's flow can always be slightly restricted, but |
| recently in submersible pump energy efficiency. | | | | never increased. Also, make sure your pump is |
| External Pumps: As their name implies, External | | | | the right size for your pond filter's specifications. |
| Pond Pumps are designed to be installed outside | | | | Water Features: Choosing the correct pump size |
| of the pond, or "in-line". External pond pumps are | | | | for a water feature is a bit more involved. The |
| a better choice for medium to larger ponds. They | | | | first step is to determine how much water flow |
| can handle greater water flows (4,000 to 10,000 | | | | you need at the discharge point of the water |
| GPH) and are less costly to operate. Other | | | | feature itself. Let's use a waterfall as an example |
| benefits of an external pump include ease of | | | | as this is the most common water feature. For |
| maintenance, longer average life, and the ability to | | | | each inch of waterfall width you need 100 to 150 |
| replace parts as external pumps are not encased | | | | GPH. So, if you have a 14" wide waterfall weir |
| in resin like a submersible pump. On the downside, | | | | you will need 1,400 GPH to 2,100 GPH of water |
| an external pump takes more time and effort to | | | | flow over the lip of the weir. |
| install, they must be camouflaged from view, and | | | | The next step is to calculate the head height. |
| they are generally more expensive than | | | | Head height refers to the approximation of the |
| submersible pond pumps. | | | | vertical and horizontal distance the water must |
| Direct Drive Pumps: Direct Drive Pond Pumps are | | | | travel from the pump to the top of the waterfall. |
| more common to external pumps as they have | | | | Horizontal distance is calculated at a 10:1 ratio, |
| the ability to draw water toward them. Direct | | | | while vertical distance is calculated at a 1:1 ratio. |
| drive pumps are appropriate for applications which | | | | For example, if the horizontal distance from the |
| require a significant amount of head height - such | | | | pond pump to the waterfall is 30', this equates to |
| as pumping water upslope for a waterfall. They | | | | 3' of head height. If the vertical distance from the |
| are generally more costly to operate than a | | | | pump to the top of the waterfall is 7', this |
| magnetic drive pond pump, but in many cases | | | | equates to 7' of head height. Therefore, the total |
| they are the only choice when a substantial | | | | head height for this application is 10'. |
| amount of water flow is needed. If you are | | | | The last step is to review the manufacturer's |
| purchasing a submersible direct drive pump, be | | | | power curve for the type of pump you have |
| sure that it is oil free, as leaking oil can harm pond | | | | selected to determine the appropriate pump size. |
| fish and aquatic plants. Magnetic Drive Pumps: | | | | Let's use the Cal Pump Mag Drive as an example. |
| Magnetic Dive Pond Pumps (or Mag Drive Pumps) | | | | The PWM3900 model is rated at 4,100 GPH of |
| are usually designed as submersible pumps as | | | | water flow at the pump discharge, but is rated at |
| most are unable to draw water into the pump. | | | | 2,280 GPH of water flow at a 10' head height. |
| The power is created through an electromagnetic | | | | This would be a good choice for this particular |
| field which turns the impeller. Their main benefit is | | | | example. Remember, it is always better to err on |
| energy efficiency and a longer useful life. In | | | | the high end of the GPH range as this will put less |
| addition, Mag Drive pond pumps are easy to | | | | strain on the pump. |
| repair as typically all that is needed is a magnetic | | | | |