Choosing the right pond pump is goes along way to ensuring the success of your water pond. A pond pump supplies your pond filter with critical oxygen to feed the microbes that tidy up your pond. It also pushes the water to replenish your waterfall.
The flow rate is the essential factor in choosing a pump. It measures the amount of water your pumps moves in an hour. It expresses the rate as GPH, or gallons per hour.
There are many factors to consider when selecting a pump. If for example, you want a water garden that will cover over one-half of its surface with plants, and have no or very few fish, you can get by with a flow rate that is less than the estimated pond volume. On the other hand, if you plan to add several fish to your pond and just a few plants, your pump's flow rate should be greater than the pond volume.
A koi pond requires a pump with a gph flow rate 2 times the size of the pond due to food and waste factors. If you are going to keep koi in your pond, you will need to know how much food they consume and the amount of waste they will generate. One follows the other, more koi, more waste. This results in the need for a pump with more power. A filter with greater mechanical as well as biological filtration will also be needed.
Many filters have special requirements, requiring a certain pumping height also known as head pressure and a predetermined psi maximum. Make sure you choose a filter that will work with your chosen pump’s specifications. Your pond's total volume combined with the number of vertical feet the pump must push water determine the pump size you need to purchase.
If you buy a pump that is too powerful you can slow it down using an in-line valve, but you can't speed up a pump that doesn’t have enough power, so choose a powerful pump. Sand filters, and many other types of filters, have a higher psi requirement and need a pump that can deliver a high the flow and pressure they need to work well. These should be shown on the filter package.
Below, you will find a checklist of a few things you should take into consideration before you purchase a pond pump:
Bigger is better - If your choice is between a pump that may be too small and one that may be too large, opt for the larger. It will keep the water flowing, even as your prefilter begins to clog.
Access - Install the pump where it is easy to get to, since you will need to clean it and change the filter on a regular basis. Also, during cold weather it will have to be moved to a higher area.
A second pump - Your pump should not be turned off for more than one hour, so you may want to consider installing a second pump. With a second pump installed you can turn off one pump without affecting the performance of your filter.
Hoses - Choose the size your pump recommends. Avoid excess length and use clips to secure the fittings. Keep the plumbing simple.
Remember, pumps need to run 24/7 and are largely responsible for the health of your pond. Careful planning before you purchase and install your pump will be a timesaver in the long run.