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Koi are prodigious waste producers, and koi enthusiasts like to keep large numbers of fish in small spaces. A koi pond must be designed to facilitate the rapid removal of fish waste from the bottom of the pond, so it should have relatively steep side walls and a smooth bottom that slopes gradually to a bottom drain. A depth of 36" to 48" is adequate, except in severe climates.

In the illustration, a concrete collar is poured in a level trench around the pond so that the top of the concrete is about 6" below the desired pond level. A pit is built to hold the filter and pump equipment. The pond is then excavated, protection fabric is laid over the soil and collar, and the fabric is covered with a rubber pond liner. Partially submerged rocks, laid without mortar, form the finished edge and conceal the rubber liner. Waste laden water flows from a bottom drain to a vortex pre-filter that settles out solids. An external pump then conveys the water through a pressure filter designed to provide biological filtration for heavy fish loads, through a UV Sterilizer (not shown) that kills any remaining algae and prevents the spread of disease, and finally into a small pond (left) filled with water hyacinths and other fast-growing pond plants that extract any remaining nutrients.


KOI POND KITS: We can custom design a complete kit with everything required to build a koi pond of any size and shape. Typical components are shown below: click on an image or title for more information. After construction has been completed, we can also ship a package of appropriate plants.

boxed liner

rubber liners

external pump


protection fabric

protection fabrics

vortex filter

vortex filters


UV sterilizers



pressure filters

pressure filters



biological clarifiers

flex pipe

flexible pipe

gate valve

valves and fittings


underwater light

underwater lights

fabric pot

fabric planting pots

bottom drain

drains and penetrations


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