Pond pumps are not complicated items. They all achieve their pumping ability by similar methods. Some pumps are designed to produce volume and others to provide pressure and it's important that we choose the right pump for the job.

It is rare that a pond pump fulfils only one purpose; more often than not there are other jobs to be done in the pond. Examples are a fountain, an ornament, a waterfall and of course filtration and there are certain functions for which the output of one pump may be shared. It may of course be possible to run all four of these functions from the same pump, but the pipe work would be horribly messy and the result not very satisfactory.

Why might it be unsatisfactory? Well, of the four requirements, two (filtration and waterfall) require a specific volume of water each hour in order for them both to function properly. Optimum volume is achieved by choosing the correct pump and by using the right size hose. A broad size hose offers less resistance to the water and allows the output of the pump to flow more freely.

The other likely jobs for our pump to do are a fountain and an ornament. Both these functions require pump pressure rather than volume. The fountain usually feeds directly off the pump and needs pressure to form its' spray pattern. This presents an immediate resistance to water flow and places a load on the pump. The requirement of our ornament is much the same as the fountain, except that it is remote from the pump (even if the ornament lives in the pond) and regardless of the type of outlet the ornament has, it relies entirely on water pressure to make it 'work'.

It's not hard to see that, on the one hand, our fountain and ornament are demanding pressure (else they won't work), whilst on the other hand our waterfall and filter are demanding lots of volume before they can possibly be effective. If we feed all these services from the one pump, the water will tend to take the path of least resistance, (that is the broad size hose feeding the filter and waterfall) and as a result, the fountain will be miserable and the ornament will get nothing. The gist of it is - choose the right pump for the job and if you need a small additional pump for the ornament, then it's money well spent.