Knowing how to select the correct pump is essential whether you need to power a waterfall or simply circulate water through your filter. Most beginning pond-keepers buy pumps for filtration. When choosing a pump for filtration, the gph (gallons per hour) of the pump is the most important consideration. In addition, the type of pond you have will determine what power your pump will need. For instance:
- Water gardens usually require a flow rate (gph) equal to half the gallon pond size.
- If you have a koi pond, you know how much they eat and how much waste they can generate. Remember that the more koi you have, the more wastes need to be removed, so you need a more powerful pump. Begin with choosing a flow rate that is twice the gph as the pond size. Choose a substantial filter with optimum mechanical and biological filtration.
- Any heavily stocked pond requires a higher flow rate.
- Make note of any additional requirements your filter may need such as a pumping height (head pressure) or a psi (pounds per square inch) maximum, then double-check your pump choice to make sure the two will work together.
- Some filters (sand filters come to mind) may require a pump that handles a higher pressure and flow rate, and have a minimum psi requirement. The filters should have their minimum psi listed on the package.
Pumps run 24 hours a day and are the chief piece of equipment responsible for keeping your pond healthy. Read product descriptions carefully to make sure you are making the correct pump choice.