A hole was dug in the ground and a concrete collar was then put around the top to support the raised wall. The liner used was a "Bradshaw" liner which is quite thin, but guaranteed for twenty years.
At the top of the liner under the coping stones there are two lengths of square rain water down pipe. This is intended to protect the liner that is out of the water from the sun, and it also gives a pleasing appearance. Eric also plans to use part of this as a surface skimmer.

The filter system is all down one side of the pond, and is made from concrete blocks. These were not rendered, but have been coated with "Brushcrete". This has been used by several of our club members in the past, and seems quite successful and suitable for filter systems. The first bay is the settlement chamber. This has a 50 gallon plastic barrel and water from the pond enters this through a 4 inch pipe. There is a circle of foam in the barrel which traps any small particles that enters, and water leaves the barrel through holes cut around the top edge. The water then flows into the remainder of the chamber and this has three rows of brushes each, and there are some onion bags around the barrel to act as a filter media.

Bay 2 which has Flocor, and plastic banding which should work the same as Springflo.
Bay 3 has 8 inch deep granite chippings, and one inch thick of Lytag. In bay4 there is a small layer of Canterbury Spar and plastic banding on top. The two submersible pumps are also situated in this bay.
The next bay is a dry space , which at the moment has only a 18 watt UV unit. Eric intends to convert this into another filter bay probably with Canterbury Spar as media.

Another bay has also been added recently, and this will eventually house the central heating pumps which are going to replace the submersible pumps. The Lowara pump goes directly to the venturi, and the Amphibious P770 pumps up to a header pond which has vegetation growing in it, and this passes along a water course which has water-cress growing in it, and then this falls into a 5' 6" x 4' 6" goldfish pond which has the water-lilies planted. The water then flows via a waterfall into the main koi pond.

Pond details
Gallonage Dimensions Construction Shape Bottom drains Filter feed Year completed Time to complete	3,950 total. 13ft x7ft x 5ft deep. Excavation, concrete collar & liner. Rectangular. None. 4" pipe run from pond bottom. 4ins pipe at mid water. 1994. 3 months
Filter details
Gallonage Type Media Bay 1 Media Bay 2 Media Bay 3 Media Bay 4 Settlement chamber Aeration	600. Concrete block coated with Brushcrete. 15 brushes & onion bags. Flocor & banding tape.. 8" granite covered with 1" lytag. Canterbury spar & banding tape. 50 gallon plastic barrel in bay 1. None.
Pump details
Type, make, etc Pumping capacity Location Water return	1 Lowara Doc3 & 1 Amphibious P770 2,000 gals/hr & 770 gals/hr. In bay 4. 1 venturi + waterfall.
Other equipment
Ultra violet lamp 2 x 9 watt.

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