How to Build a Koi Pond
Koi Pond vs. Garden Pond
When you ask “how to build a Koi Pond" first you need to understand the difference between a Koi pond and a common garden pond. The garden pond is a much simpler environment. You don’t have to worry much about the size and depth. While you may need some simple equipment like a filter and pump if you want to maintain some fish or have a waterfall feature, it’s not very complicated.
A Koi pond is a more complicated environment. Because Koi fish are fast growing and produce a large amount of waste you need to have an environment that maintains a large volume of clean, well-oxygenated water for them. It will take more space and require more equipment in the way of filtration, water supply, drainage, electricity supply for pumps, heaters and water treatment devices. It is basically a water treatment plant with fish. Ther are many decisions to be made when deciding how to build a Koi pond.
Choosing the proper location
There are several considerations in picking the best location. Choose a location that will let you view and enjoy your fish daily. Make sure you know what is underground before you start digging the hole. Knowing where water, gas and electrical utilities are located is important both so they can be avoided as well as how close they are for hook-up. You’ll need a water supply for filling and topping-off the pond. You’ll need drainage system for removing waste water, electricity for running pumps and other equipment and possibly lighting and a gas supply if you want a gas fired heater. Don’t forget easy access to the site if you plan on using any excavation equipment.
Choose the Type of Construction
The type of construction to use is a major decision in how to build a Koi pond. There are basically two common choices – a simple liner pond or a block–built pond. The liner pond is by far the simplest and least expensive. After you have excavated the pond, be sure to use an underlay to protect the liner from tears and punctures from tree roots or rocks. Liners come in various formulations and thicknesses. The best is .5 – 1.0mm thick made from plasticized PVC. Get one with a lifetime guarantee.
The concrete block pond is somewhat more complex. You lay in the bottom of the pond with a concrete slab. This is usually two slabs poured separately with reinforcing iron mesh between layers. The sides a finished with concrete blocks and reinforcing iron rods. A pond liner is often used to seal the pond, but other methods including fiberglass are used.
Pick the Type of Filtration system
You basically have two choices. You can use a pump-fed or gravity-fed system. With gravity-fed system the filter is at the same level as the water in the pond. The water flows into the filter by gravity and is returned to the pond by a pump. In a pump-fed system the water is pumped to the filter and returns to the pond by gravity usually by way of a waterfall or other water feature.
There are advantages and disadvantages to both. Do some research to determine which would best suit your particular pond layout.
Choose the Type of Filter System
Choosing a filter system may at first seem confusing but is very important in deciding how to build a Koi pond. There are several types and configurations to consider. What you ultimately choose will depend on whether you favors a pump-fed or gravity-fed system, how much space you have available and how much you want to spend.
The single chamber system while simple and less expensive is not recommended for a Koi pond because these systems cannot handle the waste loads put on them by Koi. You should consider either a multi-chamber pump-fed or gravity-fed filter.
Another choice is the vortex system. While this may not always come as part of a complete filter system they have the advantage of being able to be configured with a variety of other filter systems. These systems are ideal for dealing with heavy waste in the initial stages of filtration.
What type of Filtration Media should be Used
There are two types of filtration that you need to provide – mechanical and biological. Mechanical filtration literally traps solid waste particles and removes them. Biological filtration provides support for the growth of beneficial bacteria that breaks down pollutants in the water.
There are many types of media that are designed for each of these filtration jobs. Japanese matting has become the most widely used biological filter medium for Koi ponds. It is hundreds of fiber strands formed into a sheet or mat. Bacballs are plastic balls with a large surface area for bacteria to colonize and so are ideal for biological filtration. Flocor and Bioflow are plastic material easy to clean, lightweight and again very good for biological filtration systems. Matala is a plastic matrix sold as sheets of different thickness and density. It works much like Japanese matting but can also provide effective mechanical filtration. Foam Sheets of various grades can also serve as a mechanical filter. Brushes are common means of mechanical filtration but today I would recommend a vortex chamber for the best mechanical filtering. Finally Aquarock is used in the final chamber of a filter system to provide a final “polishing” of the water before it is fed back into the pond.
Choosing a Pump
As if there were not enough decisions to be made so far, the choice of a pump must also be made. There two basic designs – submersible and external. Submersible pumps are used either in the pond for a pump-fed system or in the last filter chamber of a gravity-fed system. However, for a gravity-fed system an external pump is the best choice. You’ll need to make sure you select a pump that has the capability to move the required amount of water effectively for the size pond you have. Your dealer or supply shop can help you make this determination.
There are a variety of other equipment such as heater, lighting, surface skimmers, aeration systems that you should also think about. As you can see there are a lot of things to consider when you ask the question “how to build a Koi pond.” Plan carefully and enjoy the fruits of your labor.
