A 'Happy Koi' Koi Pond

Ponds explained

A Koi pond should serve one purpose only. The sole purpose of a Koi pond is to provide Koi with a good home to live in which they can thrive and prosper within an unnatural environment in which their stocking densities are many thousands of time those found in Nature, even when stocking at 'only' one Koi per 1000 litres.

As such a Koi pond is utterly integrated and at one with it's filtration system. The one cannot exist without the other.

A Koi pond's primary function is to serve to continuously feed it's filtration system as efficiently as possible. Build your Koi pond around it's filtration and you will never have any hassles with your Koi pond. Do it the other way around and life is significantly more difficult.

This list is by no means exhaustive or comprehensive but it will give you an idea of some of the more important things you need to know about building your own Koi pond.

DO NOT rely on your Koi pond builder.

There are some very good reasons why we have a list of precisely one name on our list of recommended Koi pond builders. These good reasons have mostly gone out of business several times, been sued, or generally left a trail of expensive destruction behind them with Koi ponds hopelessly constructed in terms fit only for really terrible swimming pools. It is YOUR pond. YOU will have to live with it. YOU will have to maintain it. YOU will have to open and close valves. YOU will have to put up with the frustration. Your Koi pond 'builder' will not. They will be gone and your 'guarantee' will not be worth the paper it is written on.

The key to the enjoyment of your Koi pond is not the pond itself. It is the filter system. The pond is the easy, fun part.

Build your pond around your filtration

Follow this step always and your Koi pond success is guaranteed.

Remember that you are going to spending your 'koi pond working life' with the filters, not with feeding the fish and doing all that other easy stuff.

So make your life easy - and give yourself space to work with, around, on and in your filters. Arrange valves so that they are easy to access and you don't strain your back every time you do anything, or bash your head on the ceiling of a tiny filter room.

It is not important how you construct your Koi pond or what you build it with. Using long life materials will ensure a long life Koi pond. And vice versa. You can build it from concrete or pond liners or whatever you like frankly. The principles of what we are discussing here are what are important.

Do not worry about the fact that some steps look redundant or duplicate. They are neither. Each step outlined here is critical. Vital. Essential. You get the idea?

1. A Koi pond is always first and foremost a body of water in which most of the water is taken from the bottom and some of the water is taken from the surface of the pond, filtered and returned back somewhere to the pond.

2. The rate of exchange of this water from the pond through the filters and back to the pond should not be less than once every two hours. More than once every hour is excessive.

3. Roughly 75% of the water should be taken from the bottom of the pond, and 25% from the surface of the pond although a 50/50 split is acceptable.

4. It is important that your Koi are never stocked at a rate of more than one fish per 1000l of water, no matter what size the Koi may be. If you are growing top quality Koi in your pond, no more than one Koi per 2000l should be considered.

5. A minimum size pond for Koi should be around 10 000l.

6. A bottom drain of fed by 110mm pipe should be installed at a rate of one per 15 000l of pond capacity. Total filtration should comprise between 10% and 20% of the pond capacity.

7. The bottom drain pipe (110mm) should terminate in the shallow end of a settlement chamber, some 400mm below surface level of the pond.

8. The settlement chamber should slope gradually to a deeper point. At the deep end some 400mm from the surface level a suction pipe for the filters should be located. A submersible pump can be also be installed at this point for purposes of feeding a pump fed gravity return filter.

9. The settlement chamber should have a drain located at the deepest part. This drain should preferable be operate by gravity in order to empty the settlement chamber.

10. The water fed from the settlement chamber to the filtration system should be fed through a mechanical filter first. A biological filter should then follow.

11. An ultra violet light is required. Our recommended U/V dosage is at a rate of 4W per 1000l of pond water. Flowrates past the U/V light are most important - check the specifications for the maximum flowrate and design to operate at a maximum of 80% of these specifications.

12. The ultraviolet light can be installed anywhere in the filtration loop. It makes no practical difference. So install it where it is easily accessible. You will need to change the globes every 8 to 12 months. Make your life as easy as possible in this regard as UV lights are bulky cumbersome things once installed.

13. Once the water has passed through a mechanical filter it should be passed through a biological filter. Residence times in the biological filter differ from filter to filter. Check with your manufacturer and ensure that the water flows through the bio filter at 80% or less of the maximum flowrate the filter specifies.

14. If a flow rate or residence time is not specified, DO NOT use the bio filter. It will not have been designed with a proper Koi pond in mind. If it looks small, it IS too small.

15. Once the water has passed through the biological filter it can optionally be passed through a vegetable/plant filter.

16. Once the water has passed through the vegetable/plant filter it can be returned back to the Koi pond.

17. Water should be returned at or slightly below surface level. Optionally some water can be returned deeper but not more than half of the maximum depth of the Koi pond.

18. Use logic to dictate where to return water to the pond to avoid any 'dead spots' of inactive or water without movement within the Koi pond.

19. No evidence exists to suggest that deeper water returns have any positive effect on Koi development or health.

20. If you are using pipe, water returns should never extend beyond the wall and protrude into the Koi pond. Nothing should protrude into the Koi pond - including decorative rock work or similar.

21. It is not necessary to have pressurised water jets in the pond for the Koi to exercise against. In the ultimate Koi pond, stocking density and overall pond will play a far larger and more significant role than supposed exercise for your Koi.

22. Optionally additional water circulation loops can be included in the ultimate Koi pond. These play no role in respect of filtration and are only installed to provide additional water movement.

23. Aeration is not optional and is mandatory in any Koi Pond. This can be achieved by airstones or air curtains. It requires an airpump to deliver bubbles into the pond from a minimum depth of 2/3 of the depth of the Koi pond.

24. Venturis and waterfalls are not acceptable aeration devices.

25. Regular maintenance and water changes of 5% to 10% weekly (replacement water lost through filter maintenance counts toward this figure) and feeding of your filter bacteria with replacement trace elements completes the picture of the Happy Koi Koi Pond.

26. Spend good money on good quality valves. Valves on a Koi pond are used a lot more than you might suspect. A good quality valve will remain easy to operate for years and you will respect the investment you made in it.

That's it. The 'Happy Koi' Koi Pond is yours. All you have to do now is maintain it. Maintenance will comprise mainly of filtration maintenance according to the manufacturers specifications. It is suggested that you also adopt a conservative approach with respect to these figures and carry out maintenance more frequently than specified.

It all starts with your filters - read all about it now!

or Check out the forum - ask your questions here.