Splashing water over the blooms of water lilies will waterlog the flowers. Therefore some thought has to be given as to the site of a waterfall or fountain in the pond, the strength of flow and whether and what plants are to be grown in it. The first consideration is what use the pump is to be put to i.e. a fountain or waterfall, high or low voltage. It is necessary to know the height to which the water must be lifted and the volume of water. For waterfall installation a pump which produces volume rather than pressure is required, for fountains the reverse may be necessary.
Submersible pumps are the most satisfactory and economic type for small and medium sized pools.
They should be sat on a brick in the pool to avoid being clogged by silt or debris, and must be completely covered by water to avoid damage. If the pump is high voltage, then an outdoor power point must be installed by a qualified electrician. A fountain jet may be attached to the pump depending on the pump model or a hose may be attached to supply water to a fountain ornament. A submersible pump supplying a waterfall should be placed as close as possible to the point where water re-enters the pool to minimize disturbance which water lilies resent. The selection of plants is most important.