the koi pond
koi menu
Completed July 2003
the Fish
There are presently 42 fish in the pond of which there are:
- 28 Koi, varying from 5 to 18 inches
- 2 Red Comet
- 8 Shibunkins
- 4 Green Tench
Features
The pond is basically three interlinked pond units.
The main pond is 9ft x 5ft x 5ft deep, containing all the fish.
The filter tank is 9ft x 1.5ft x 1.5ft deep, at the same level as, and behind, the main pond - so is all gravity powered. This is divided into 6 x 1.5ft sections:
- is where the water enters from the main pond into a centrifuge. This separates out the heavier particles and feeds into
- the brush unit, to filter out the bigger particles, before entering
- the 'hair rollers'. The bacteria colonising this begin the conversion of the Ammonia to Nitrites then into Nitrates.
- coarse matting comes next. Again the bacteria colony continue the process.
- This is followed by foam which filters out the remaining fine particles.
- Last of all is a settling/holding tank from which the water is pumped back up to the upper pond, via a UV lamp unit.
The upper pond is a quarter circle, of about 5ft radius and 1 ft deep. This has been filled with shingle and all the plants live in this section. This has two advantages:
- the Koi cannot eat the plants
- the plants use up the Nitrates
The clear water then returns to the main pond over a waterfall. The waterfall, apart from being a visual feature, also re-oxygenates the water.
As the rear of the filter unit runs along the garage wall, all electrics are housed inside the garage.
Design
The pond plans are:
The filter unit:
Construction
The construction is of concrete blocks cemented on a slab base, into which two bottom drains were incorporated. The whole is internally rendered, with the rendering including fibreglass strands.
The finish coating is green coloured P1.
Pictures
The upper pond with plants:
The filter unit along the back of the pond, against the garage wall.
Feeding time for the Koi.
