Pipework for Bottom Drains

When you have decided which type of pipe you are going to use then you need to decide if you are going to connect the bottom drains directly to the main drainage or to the settlement chamber of the filter system. The sketches below show the different ways of doing this.

The diagram above shows a typical pond layout where the bottom drains go direct to waste, and the feed for the filters are taken from mid water. This was popular in the eighties, but now the recommended way is the system shown below.

The diagram above shows another pond layout where the bottom drains constantly feed the first bay of the filter system, which in fact is the settling chamber. The drain from the settling chamber is connected to a slide valve, or stand pipe, in the discharge chamber.
This method continously removes waste from the pond, but it is necessary to have a very efficient settlement chamber which is cleaned regularly.

TIP. In the drawings above the stand pipes in the discharge chamber can be lifted to release the water to the main drain. This way was very popular until the mid eighties but now that slide valves and ball valves have come down in price then most koi keepers prefer to use them instead.

With the bottom drain connected to the settling chamber then as mentioned above we need a very efficient method of removing the sediment without losing too much water, and the popular way is to use a Vortex Chamber.

This website started with a booklet which I made up originally for the help of those members of the BKKS - South Wales Section who were intending to start building a koi pond, and as the website has expanded more information and articles from other people have been included. This is for general guidance only, and we do not take any responsibility for problems that might occur by following these ideas. It is important that you check out everything in your area, and check on local laws and rules that may apply.


A Guide to Modern Koi Pond Construction Pipework for bottom drains
We have looked at bottom drains and it is now time to consider what pipework we should use, and how we are going to lay it out. The best pipe to use for the bottom drains which are nearly always four inches diameter is uPVC pressue piping. This is considered by some koi-keepers as very important as it will be buried in the concrete, and any failure in the future will mean problems with the whole pond. The pipe mentioned above is very expensive, and the majority of koi-keepers argue that as it is buried in concrete then it will not be disturbed and so will not give any problems if you use terrain pipe. It is said that this terrain pipe carries away all the waste from the house and is in constant use, but it should also be borne in mind that with a pond the pipe is under pressure all the time which does not happen when used for household purposes.
	If you have decided to use terrain pipework then there are two different types. These are easily identified by their colour. One is grey and the other is rustic brown and usually referred to as orange. They are both the same size and 110 mm in diam. The orange pipe is designed for use underground and is connected with seal rings, and solvent should not be used. The grey pipe is used for runs above ground, and they are joined together using solvent. They are connected together using fitting with the seal rings. The fittings mentioned here are to British standards, and will be different in other parts of the world.
	This photograph shows bottom drains and pipework laid out using terrain pipe. Bends are used at the end of each pipe and the verticle pipes go straight up to the stand pipes in the discharge chamber. When ordering bottom drains remember that you require 110mm for terrain pipe, and 4 inch for pressure pipe.
When you have decided which type of pipe you are going to use then you need to decide if you are going to connect the bottom drains directly to the main drainage or to the settlement chamber of the filter system. The sketches below show the different ways of doing this.

The diagram above shows a typical pond layout where the bottom drains go direct to waste, and the feed for the filters are taken from mid water. This was popular in the eighties, but now the recommended way is the system shown below.

The diagram above shows another pond layout where the bottom drains constantly feed the first bay of the filter system, which in fact is the settling chamber. The drain from the settling chamber is connected to a slide valve, or stand pipe, in the discharge chamber. This method continously removes waste from the pond, but it is necessary to have a very efficient settlement chamber which is cleaned regularly.
TIP. In the drawings above the stand pipes in the discharge chamber can be lifted to release the water to the main drain. This way was very popular until the mid eighties but now that slide valves and ball valves have come down in price then most koi keepers prefer to use them instead.
With the bottom drain connected to the settling chamber then as mentioned above we need a very efficient method of removing the sediment without losing too much water, and the popular way is to use a Vortex Chamber.
This page updated January 2004
This website started with a booklet which I made up originally for the help of those members of the BKKS - South Wales Section who were intending to start building a koi pond, and as the website has expanded more information and articles from other people have been included. This is for general guidance only, and we do not take any responsibility for problems that might occur by following these ideas. It is important that you check out everything in your area, and check on local laws and rules that may apply.
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