How To Design Koi Pond

Photo, Lagunakoi Colection

KOI POND DESIGN -- How to step by step to design Koi Pond ? Following are excerpts from the Water Quality Seminar hosted by Olympic Koi Club on February 19, 2000 featuring Tony Prew (noted filter specialist) and Dick Benbow (noted water quality expert.) The article is written from notes recorded at the seminar by Tim Putaansuu who is more knowledgeable in web site design and fluid systems than water quality and filtration, so no guarantees of accuracy of this information are given. But you can used this guideline to make your own koi pond design.

Step By Step Koi Pond Design

Koi Pond Size

Pond length should optimally be 2.5 times the width and 6 to 8 feet in depth. Pond volume should be 1000 to 2000 gallons for every show quality fish, or, for the rest of us, 100 gallons for every foot of fish. If your fish tend to be fat and short like footballs, they are too crowded.

Koi Pond Filter Guideline

Ideal Koi Pond volume should be turned over once every two hours. Both Tony and Dick mentioned their skepticism for any filter that claims to do it all. They insist that separate mechanical and biological filters are needed. They also note that any filter design should be easy to maintain so that one might actually maintain it. If a filter system clogs too quickly and/or is difficult to clean and maintain, then it will not be cleaned often enough and water quality will suffer. They presented pea gravel filters as an example of this. They tend to pack with debris too soon, and yet, are heavy and difficult to overhaul and clean.

Tony outlined his filter system as an example of an optimal system to strive for. His system starts with a 6" pipe from the pond bottom drains to the vortex. In the vortex, the solid waste is gently flung to the outside perimeter of the vortex where it drifts to the bottom where it can be definitively flushed away by opening a 4" drain valve, while the water, free of most of the debris, is allowed to flow to the second chamber which houses 96 oversized, pipe cleaner looking, 24" brushes. These brushes mechanically filter out any debris that may have gotten past the vortex chamber before allowing the water to flow through the biological filter.

Collecting and quickly disposing the majority of the solid waste prevents that waste from contributing to the biological load of the pond. Tony uses two chambers in series for his biological filter and speaks highly of the Japanese blue poly vinyl chloride matting that he uses to stock them. He stacks the mats on top of each other using dowel spacers between the layers making up a matrix a total of 12 inches thick.

UV Sterilization

Although they don't necessarily believe in UV sterilizers, since they tend to mask developing filtration problems, Dick and Tony both admit that a UV sterilizer may be utilized between 52°F and 60°F to minimize the spring time green water that is normally experienced while the filter system wakes up from its own dormancy. The UV sterilizer is also useful in this temperature range to cut down on the parasite population while the Koi's immune system is not yet fully functioning. If the UV sterilizer is needed past the 60°F temperature to maintain pond clarity, then a problem exists in your filtration system that needs to be addressed.

Pond Heating

Pond heating may seem like an exorbitant expense. Tony heats his pond to 65°F using an electric spa heater to the tune of $200 a month. Tony believes that with gas heat, that bill could be reduced to $50 to $75 a month. To help contain this cost, Tony suggests that your pond be insulated with foam or equivalent during construction instead of the protective padding normally used such as felt or carpet. Heating the pond allows one to enjoy your Koi year round and allows for maintaining a summer temperature a bit higher than is normally seen in this northern latitude.

A warmer summer season allows for more active fish and higher growth rates leading to larger fish. However, considering the expense and the advantages of dormancy mentioned above, most of us will not elect to heat our ponds year round. Some advantage could be seen in installing a heater but using it mainly to help define the transition from activity to dormancy and back again. This helps prevent the false spring problem of having the temperature rise above 52°F where you start to feed the fish only to have the temperature fall back below 52°F and risk having all that food rot in their stomach. One can instead dust off the heater and turn it on for the next week or so to keep the temperature above 52°F and maybe even to 55°F where the immune system is more effective.

In fall, one can forestall the drop below 52° until the weather is cool enough that you know that the pond will smoothly sale through to 45°F to minimize the time spent in the parasite friendly zone. Manipulation of your pondís temperature should be undertaken with care. Rapid temperature changes are stressful to fish and may be fatal if the change is great enough.

Source:
http://www.olympickoiclub.org/ponddesign/guideline.html