A Guide to Modern Koi Pond Construction

In fig 19 below we can see the basic system.
In the last bay we have a strainer which prevents any of the media, leaves, etc. being drawn into the pump. This is especially important if the pump does not have it’s own filter basket. If the last filter chamber has Japanese matting the strainer may not be necessary, but you have to be careful with leaves and other debris.

From the discharge side of the pump the water flows to the UV unit and then to the pond, usually using a venturi.

NOTE. In this drawing a swimming pool pump is shown, but any type of pump can be used. The valves shown are slide valves as they are easier to draw, but again these can be ball valves and in fact these are usually considered the best option for this application. Valves are shown on each side of each unit so that they can be removed or opened up without disturbing the whole system. If they were situated as close as shown then only one valve would be required between the pump and UV unit.

Fig 20 shows a similar system, but this time a heater has been added to the system. (See separate pages for heater details).

NOTE. When ever you are fitting one of these units then carefully read the instructions supplied by the manufacturer. If for any reason you need to connect it up in a way not mentioned by the instructions then do contact the manufacturer, or get expert advise.