Large Koi ponds need many more pipelines than smaller Koi ponds; feed lines and return lines from skimmers, feed lines and return lines from filters and return lines to waterfalls etc.

In earlier days, these lines were taken around much of the pond perimeter and the resulting friction loss in these very long lines resulted in having to purchase more powerful pumps and pay the higher running costs involved.

For some years now I have adopted another approach to this problem, which may be of some use to others who are considering building a large Koi pond.

For example if the proposed pond is to be six feet (180cms) deep then the initial excavation should be seven feet (210cms) deep.

Once the excavation has been made then 2” (5cms) of hard core should be added and then packed down firmly –

After placing a suitable waterproof sheet on top of the hardcore then feed lines and return lines from skimmers and return lines from filters can be installed directly on top of this sheet –

This allows us to shorten the lines significantly by going directly from supply to return.

The next thing to do is to fill all these lines with water to make sure all lines are watertight.

After this is completed a prime 6” (15cms) concrete base can be poured to encase all the lines.

This means we now have a flat slab of concrete where the bottom drains and the diffuser airlines can be placed and taken directly to the filter area. Again it’s vital to ensure that all these lines are watertight.

The pond walls can now commence until they are 3 feet (90cms) high and the return lines can then be installed into the pond like this – please note this shot is not of the same pond but it does explain how the return lines are installed.

The pond walls can now be completed to the required height, and after this, the walls can be rendered, the base can be benched and the pond can be laminated by glass fibre.

It’s simple, it’s logical and saves on pipe work and fittings; it also reduces running costs.

Waddy 02/05/13.