Understanding Modern-day Principles of perfect pond design

Throughout this section of my site I will be covering all the aspects of Koi pond design and build methods and I will be referring to all of these in great detail. They are, however, based on the best way to go and, believe me, there is only one BEST way to go – everything else is merely a compromise and I am not best known for compromise in any aspect of Koi pond design.

(Warning – this is lengthy by nature!)

I will repeat once again a sentence I first published in 1995 which is:-

‘The cheapest possible way to build a proper Koi pond is to build it once……………but build it properly’

’This statement is still as true as ever.

For starters there is nothing ‘natural’ about building a pond in one’s garden and please walk away from those who preach otherwise.

  • Is it ‘natural’ to dig a hole in one’s garden?

  • Is it then ‘natural’ to make it waterproof with a man-made rubber membrane or concrete instead of soil and clay?

  • Is there anything remotely ‘natural’ about a plastic or metal water pump?

  • Is there anything ‘natural’ in a plastic water fountain?

  • Are assorted water plants retained in plastic containers ‘natural’?

  • Is a body of water having no constant inlet of new water and no constant outlet of old/overflow water ‘natural’?

  • Is the action of adding fish life to a body of water ‘natural’?

  • Is the daily feeding of man-made fish food ‘natural?

  • Is the manual removal of dead leaves, decaying matter, dead plants and dead fish ‘natural’?


The only answer to the above questions (and I have dozens more) is a resounding ‘NO’.

Because I soon discovered, long ago, that there is only ONE maker of natural ponds in the world and that is ‘The Great One Above’ who is the sole master in this field.

His ponds can take decades to ‘evolve’ and not a mere five weekends of hard labour by one or two mere men. His ponds DO produce a fine and natural balance that incorporate the minerals within soils and clays of the walls and base. Then follows the gradual addition of hundreds of types of water insects and algae forms, a constant entry and exit of new water, the gradual build-up of water plants, incredibly low numbers of fish life and crustaceans taking into account the enormous volume of water and thus the system continues to evolve and mature completely naturally year after year.

If ever, the fish stocks reach a very high level then nature steps in with a natural disease or virus that destroys all but the strongest and thus the marvel continues.

This can be witnessed even better by the wonders of most of our rivers in the UK today after man has finally realised he can no longer continue to empty chemical waste and other lethal hazards into them. As a result of this, today our wonderful revived river systems show us all just how incredible they are intended to be without the disastrous and criminal interference made by man.

For newcomers to keeping Koi, please remember, despite the hogwash spouted, even today, by garden centre outlets and some Koi outlets the world over – there is nothing even remotely ‘natural’ in building a garden pond in which to keep Koi, or any kind of fish life for that matter.

Instead, and this will be explained later in great detail, just about every Koi pond I know of today uses much of the basic ideas and equipment that have been incorporated and adapted from indoor aquarium technology be it cold water, tropical or marine. The real difference between aquarium keeping methods and Koi ponds is that of the huge water volume differential.

As a result and despite what a few may profess, a garden Koi pond IS an ‘Outdoor Aquarium’ – plain and simple and completely man-made – that is a solid FACT!

(I can only think of one or two situations where a garden Koi pond can produce ANY natural conditions. One is the simple reaction between natural daylight and most bodies of water whereby many different types of algae form. The other, which is also dependent on the supply of algae, is where many forms of natural insect life can exist and reproduce.)

After that we must realise that we mortals are attempting to simulate some of the better aspects of a natural pond by man-made methods and technology.

The good news is, it can be done and, today, it can be done FAR better than ever before.

To ‘Build it Properly’ means using the following methods and forsake all others because the others are simply compromises:-

CONSTRUCTION – build a concrete block pond and avoid liners like you would swine flu.

Today, the majority of ‘proper’ Koi ponds are constructed from concrete blocks and concrete bases and then waterproofed afterwards from a choice of available materials ranging from rubberised paints, resins and glass fibre laminating.

Pond liners and other waterproof membranes have long-since been avoided as a choice for modern-day Koi systems. In truth, these should never be used for deep ponds with vertical walls. There are important reasons for this, liners are perfect for use in standard shallow, garden ponds that are formed with planting shelves and have no pipelines to connect to them. The majority of these excavations are merely shallow saucer-shaped indentations in the ground with no real sidewalls as such. Often, pebbles and stones disguise many inferior pond bases to conceal the ugly creases below, which trap endless detritus – please beware; this is Disneyland with a greater hidden danger!

A Koi pond system however, is a different beast whereby several large pipeline connections have to be made to supply the filter system and to accommodate return lines; a Koi pond also must have steep, vertical sidewalls.

The most important reason we should not incorporate liners on a vertical-walled Koi pond is that ground water can and does track down between the liner and the soil behind. As this continues to occur, soil erosion takes place and this forces the liner to compensate by stretching. Once no further ‘stretching tolerations’ can be made, the liner simply bursts by sheer pressure of water.

Over the years I have been involved with all forms of liners both flat-sheet and box-welded tailored ones for individual ponds but cannot recall any installation where the pond base (the most important single aspect of any pond) has been perfectly smooth and this is useless in my book.

Whilst I am aware that most liner manufacturers do give a lifetime warranty for their products, they will never refund the cost of removing the damaged liner, the packaging and return transportation charges or the cost for re-instating it into the ground. Nor will they pay for the cost of re-housing the Koi during this period, please do bear this in mind.

I last sold a butyl pond liner in 1984 through experience – I do hope I have made myself clear on this matter.

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