This 5,600-gallon pond has 9" thick concrete block walls, rendered, and then fibre-glassed.
The pre-fabricated fibreglass filter module consists of four chambers and a discharge box. This was a standard module as supplied at that time by Infiltration. Each chamber is octagonal in shape, 42” wide, and 24”deep to the media support tray (diagram below). The void space below this is 12”deep and is benched. The base of each chamber has 4 X 100 mm cylindrical air stones installed to ensure no settlement.
Each chamber has a two-inch drain at the base, which is connected to a separate valve in the discharge box.
There is an overflow in each chamber (except the K1 chambers) to remove excess water, floating debris, and the protein layer from the surface of the water. The discharge box itself has a four-inch waste pipe to take the wastewater to the house main drains.
The pond has three bottom drains connected directly to waste via the discharge box, each with separate 4-inch diameter pipes, and these are connected to stand pipes fitted with "O" rings. The drains are flushed to waste several times a day.
A miniature Torbeck valve in the final chamber controls the automatic water top-up facility.
Electronic float switches are fitted to Bay 4, which will automatically switch off the pumps in the event of a major leak, or should the pumps be starved of water for whatever reason.
The gravity feed from the pond to the first chamber is via a six-inch pipe, and takes mid-water from the pond side. Aeration is supplied to the second, third, and final filter chambers. The air is supplied to the filter system via three Airtech 80 air pumps and one Airtech 40. The first chamber has small Flocor, the second chamber has 200 litres of Kaldnes K1 and 100 litres Biochips, the third has 150 litres of Kaldnes K1 and 100 litres Biochips, and the forth chamber has a 16” deep Japanese Matting cartridge which is heavily aerated from underneath. Each of the Kaldnes chambers has 80 litres air per minute supplied.
The Flocor in the first chamber is contained in open net bags so that they can be easily removed for frequent cleaning and maintenance. Click here to see the Kaldnes conversion.
The water is pumped from the fourth bay by a 3/4 HP ITT Marlow pump through a 30" Lacron Sand Pressure Filter, filled with AFM glass media. The sand filter is back-flushed every day of the year.
The clean water then passes through an indirect gas heating system (Potterton, 60,000 Btu, Kingfisher domestic boiler, fitted with a 230,000 Btu stainless steel heat exchanger) returning to the pond through a 55W UV and then a waterfall and venturi.
A surface Skimmer is also fitted, which is operated with a 1/2 HP ITT Marlow pump, and the water is circulated via a deep water return directly to the pond.
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.
