pond pumps are perfect for medium to larger pond sizes.
For example: a pond that contains one thousand gallons of water or
more is a good candidate for one. This kind of pond pump is particularly
good for larger ponds because it is energy efficient. The cost of
using a submersible pump in a large pond can be much higher.
Also, external pumps can handle larger water flows.
And an even further benefit of this type of pump for a large pond
is that it works well with biological filters.
Regardelss of whether you get a submersible or external pond pump,
you want to be sure to get a pump that will circulate the entire volume
of your pond at least once per hour.