Pond Construction 1993
After watching Dad (Jan 1993) transform a garden bed into a fish pond (Dad's Pond) , my interest in Koi and ponds grew. I spent the next 6 months looking and learning. Each weekend I would go and have a chat to the local Koi breeders and pond suppliers to gather as much information as I could.
In July 1993, I started planning the building of our fish pond still with many questions that were unclear in my mind. I knew that I had to build the fish pond, waterfall, filter system and landscape around the pond. My first step was to go and purchase a pre-cast fibreglass pond, which I used as a starting point to make the fish pond.
As the house was built up 700mm from the natural ground level and I wanted the pond directly behind the patio at the same height, I had to build a small retaining wall. The retaining wall was done as two stages. The first stage, which forms the back of the fish pond was constructed with pine pines cut in half, this also formed part of back of the waterfall. The second stage, was constructed from moss rock which runs back up the back patio.
Once the retaining wall was complete, I was able to dig the hole for the fibreglass pond and as I was digging in sand this was an easy task. Once the hole was dug, I then cut a 50mm hole in the base of the fibreglass pond for the pipe that supplies the biological filter. The hole was cut using a 50mm hole saw. Once the hole was cut, it was fitted with a 50mm valve takeoff (bottom) and a 50mm faucet socket (top) then sealed with silicon to form a water proof seal. The plumbing was completed by running 50mm pipe down to the filter system The pond was then placed in the hole, back filled, filled with water and left to settle for 7 days.
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Fibreglass pond just after it was backfilled and filled with water. |
When the pond had settled, a 150mm concrete strip was poured around the top of the pond to form the base for the moss rocks. We also poured the small pond at the base of the water fall. When mixing the concrete for the small pond we added aquapell to help water proof the concrete. The small pond and the concrete strip was left to cure for 14 days before we started placing the moss rocks around the top of the pond. Whilst the concrete was curing we started the construction of the biological filter system.
| Pond just after the concrete strip had cured. We have just started to place moss rock around the top of the pond. The small pond that is at the base of the waterfall can be seen to the left of the picture. |  |
When the filter system was complete, we started placing the moss rock around the top of the pond and the small pond. We also started forming the shape of the water fall.
Once we had placed the moss rocks and were happy with the position, each rock was removed and cemented back into place. When the cement had dryed the joint between the fiberglass and the cement was coated with Silicon Glaze. Six coats were applied with 2 hours drying between each coat. This formed a water proof seal between the rocks and fibreglass which was going to be required as the water level is approx 50mm above the top of the fibreglass. Todate there have been no leaks.
During the construction of the waterfall we brought a 25mm pipe up the middle of the waterfall from the filter system.. The waterfall was constructed using moss rocks, with one large rock forming the front and another large rock forming the base for the water to flow from. The water return pipe was brought in back of the waterfall a small 100mm x 90mm basin was made for the water to flow from. The width of the waterfall flow area is 200mm.
Once the pond, rock work and filter was finished the entire system was filled with water and the pumps tested. Over the next few days the entire water was changes twice to lower the pH level to 7.5
Once the pH level was correct we introdued a couple of water plants and a week later added the first 5 koi.
Filter Contruction
Once we had completed the initial work on the pond construction, we start work on the construction on the filter system, as the filter was going to require approx 3-4 weeks to allow the concrete and rendering to cure sufficiently before establishing.
Our first step required us to dig a hole 1100mm x 700mm x 600mm deep for the filter. We also ran a 50mm pipe from the pond down to the filter box which would be the feed from the pond the the filter. When the hole was complete we poured the re-inforced concrete slab which was 75mm thick. The slab was left to cure for 14 days. When the slab had cured we began building the filter system. The filter consisted of three chambers. The first chamber as a pre filter for excess food, large plant matter etc, the second chamber as the biological filter and the third chamber contained the pump to return the water back the fish pond.
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The whole where the filtration system is to be constructed (just after it was dug). The approx dimensions are 1100mm (44in) x 700mm (28in) x 600mm (24in). The feed pipe from the main pond can be seem in the bottom center of the picture. |
The filter system was constructed from brick with a 40mm pipe connected the first chamber to the second and the second chamber to the third. The pipes were built in the walls, feeding from the bottom the chamber and returning at the top of the next chamber, this is to ensure the water passed through the filters.
When the brickwork was complete the walls were rendered to a thickness of 10mm to waterproof the filter system. When the render walls were dry the entire filter system was coated with Silicon Glaze, a clear water like silicon which forms a water proof seal and stops lime etc leaching into the water. We applied 3 coats to the walls and 4 coats to the concrete floor.
| Filter Box just after it was finished. Chamber 1 front right, Chamber 2 top right and Chamber 3 left. |  |