Reflections Koi Pond Experts Northwest UK
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Filter Housing
The filter housing had to be capable of walk in access. All the filtration equipment and associated pumping equipment was to be located in this housing. The housing concrete base was cast to accommodate our chosen filtration system. All the Koi pond electrical requirements were to be supplied from this building. A new power supply was installed to meet this requirement. A new mains water supply was also run to this building. We had detailed scale drawings of the inside of the filter room which allowed careful placement of pipe work before the floor was cast.

12000 Gallon Koi Pond Project - Filtration
Outlined over the pages below is a detailed description of how Reflections constructed a 12,000 gallon Koi pond.
12000 Gallon Pond Home Page
Pond Construction
Filtration Installation
Finishing Touches
Pond Building Landscaping Filtration Automation GRP Liner Maintenance
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These drawing allowed us to position the pipework with minimal finished pipework exposed. The filtration equipment was simply dropped into place and plugged in. The filter room floor was tiled with a porcelain tile which allows the whole room to be hosed down. The filter housing was constructed from dense concrete block, engineering brickwork and coursed walling stone which complimented the existing construction materials. The filter housing roof was to be tiled to match the dwelling. A Velux window was incorporated to allow daylight and ventilation into the filter room. White PVC soffit and fascia boards were added along with rainwater goods – these work very well with the coursed walling stone.A rainwater collection system was installed around the filter room and greenhouse to allow for the correct management of rainwater. Ultimately a rainwater harvesting system will be incorporated to offset utility charges for water changes. A 6” sewer was laid to collect filtration discharge water and waste rain water this was connected to the existing dwelling drainage system.

Filtration Equipment
Our client has kept Koi for over 28 yrs and had very specific requirements regarding his chosen filtration system. He has tried most systems over the years and, being the thinker that he his, wanted things his own way! Who are we to argue? We tried and tried..... welcome to the world of AE technologies! Filtration can be broken down into 3 basic stages : 1/mechanical 2/biological 3/chemical
1/ mechanical filtration is a means of removing solid waste from the Koi pond and thus preventing the solids from becoming soluble. The chosen 1st stage mechanical filter is something we call a PAST – a Passive Aerated Settling Tank – this is basically a tank of aerated water that removes the bulk of the initial solids. Sounds strange but if the air is introduced in the correct manner then the amount of solids that are settled to waste is amazing.The next preferred method of mechanical filtration is by using a Cetus sieve. These Cetus are fantastic as a pre filter or after a surface skimmer to remove leaves and surface debris. On this system we utilised a Cetus after a surface skimmer. The Cetus units are manufactured by Evolution Aqua Ltd in Wigan, Lancashire. Once leaving the skimmer the returning Koi pond water passes through a Aquadyne bead filter and then a UV light. The Aquadyne bead filters are distributed by Cascade Water Gardens in Bury, Lancashire. The removal of solids is very important to the efficiency of a bead filter and the Cetus provides the correct amount of protection.
2/ biological filtration is pure and simply the nitrification cycle. A home for bacteria to grow and do their stuff. The clients preferred choice of biological filtration for this Koi pond is Japanese matting. This Japanese matting was located in a filter unit designed by Peter Waddington. We removed the brush part of this system because the PAST is more efficient and less labour intensive regarding maintenance. We also removed the standpipe that is used for discharging and utilised a 4” double union ball valve for ease of maintenance.3/ no provision for any type of chemical filtration was allowed for in this design.
Filtration System Operation
In this design we chose not to use the bottom drains to feed the filtration system, opting instead to use mid water feeds. This Koi pond has two aerated drains located in the base. One of these aerated drains is a purge direct to waste drain only. The second aerated drain is fed to the Cetus sieve. The surface skimmer is also connected to the same Cetus. An assembly of 4” valves and 4” tee allows the user to choose which source to pull from. Each the two 4” inlets also have a purge to waste assembly which if used regularly, will reduce the waste loading. Leaving the Cetus the water passes through the Aquadyne 1.1b bead filter then flows through a ProClear 110 watt ultra violet clarifier. The water then returns to the Koi pond via one of the three TPR’s.
Two 225mm mid water filter feeds were incorporated, each mid water feed has a 4” outlet. Water flows from each of these feeds into the primary settlement chamber – the PAST. The majority of the solids are removed here. This chamber has a 2” discharge line direct to waste. Water exits through a 6” tee branch which is then split into two 4” lines. Each of these lines then feed the matting chamber. Water exits from these chambers and is pumped to the two remaining TPR’s.
System Pumps
The chosen system pumps were Sequence pumps. They were chosen for their reliability and low running costs. One Sequence 18,000 litres per hour pump runs the Cetus sieve and two Sequence 12,000 litres per hour pumps provide the returns from the ERIC Japanese matting filters. The total running cost for this system is approximately £400.00 per year or £1.10 per day.
Ultraviolet Clarifiers
The pond has a surface area of 20 meters and until mid afternoon will be in full sun, so we have used two UV clarifiers on this pond. The first is ProClear 110 watt unit. The ProClear was specified due to its high flow capacity and proven performance. The ProClear has 2” inlet and outlet connections which is an advantage when combined with the other systems components. The 2nd UV chosen was a Zapp Pure 20. This is an upright UV, which helped with locating the UV in the filter room. The ZAPP Pure also has 2” connections and a high flow capacity. Continue..