A koi pond is a purpose built habitat "Living Jewels" and as such, differs from any other garden water feature. Instead of doing what so many do, that is dig a hole, throw in a liner, add water and a few fish, and calls it a koi pond. You can't put more than about 20 full sizes Koi in a 2,000 gallon pond, and to do that requires a lot of filtration and aeration.
Koi pond’s requirements
Means you can't stand up in it without taking out a lot of the water, but it will make it a little more difficult to clean out your pond. Locate the pond out of direct sunlight all day long. If you have the money a gas pond heater for cold climates is recommended. Very few ponds have a protein skimmer, but they are very useful to reduce the organics causing the foam under your waterfall, etc. Proper filtration system is must for survival of koi. The returns through the sides of the pond from the filtration system will produce a bit of a current and keep particulate suspended and headed for the bottom drains or skimmer.
Koi pond with a liner
It is easy to manage but liner must be Eco-friendly, because koi are extra sensitive. The only difference between a liner pond and any other is what's used to contain the water. All other technical aspects are the same.
Maintenance of koi ponds with their types
It is very important to save you pond from leaking. Large leaks in ponds are very easy to identify but most pond leaks are small and can be quite deceiving at first. A small leak in a pond can be a very hard and expensive problem to solve if you do not know how best to tackle it.
Different types of pond
1) Concrete or rendered brick
these types of pond are usually sealed with some kind of resin or pond paint. You first need to check for cracks as this is the most likely reason your pond has leaked. To fix this you will need to cement the crack and re-seal or use a product called pond liner repair just fix it. If it seems to peel away or is non-existent you will need to re paint it as it has become porous or patchy.
2) Fiberglass /GRP
A pre-formed GRP pond is the toughest of all the pond linings but can still suffer from water loss. Before you do this you may want to try covering the area with just fix it Pond liner repair kits or use a liner repair patch, they are not full proof but I have had some good results employing these methods.
3) Molded plastic
Molded plastic ponds can be fixed with pond liner repair patches. They suffer with the same problems a GRP ponds does but are far less common.
These are the most common types of lining. Pond liner repair is useful for all type of pond with surety of koi survival.