Added on: April 6th, 2007

Bridge over the River Koi

Shade sail and Bridge over the River Koi completedHaving kept Tropical fish since my early teens, I’d wanted to expand my hobby to include a proper Koi pond. Eventually in 2003 my family and I decided to do away with a less than impressive Goldfish pond and flower bed and build a Koi pond. At the same time we wanted to tidy up a tatty corner of our garden. My two youngest kids (Patrick and Caitlin) helped mark our new pond with rope. Our eventual design had to accommodate several obstacles such as a small cherry tree and a conveniently located’ soil pipe running diagonally across the lawn. Budget and ease of construction meant that we were going to build a raised liner pond, so a trench for the concrete collar was dug.

I was lucky enough to have a mate (Neil Owen) who’d been putting in some decking around the other side of the house. Neil graciously helped with concreting the collar. My wife Mags suggested adding a small bridge in the design, partly for fun, but also to offer the Koi some cover. The supports for a small bridge were concreted in at the same time.

My youngest daughter Caitlin and I begin digging the collar
My youngest daughter Caitlin and I begin digging the collar

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There was a delay between the collar being completed and the actual Pond excavation commencing mainly due to a bit of a ‘health scare’. Once back on my feet my attention returned to the pond. I was going to use the excavated soil to landscape around the new pond, rather than being loaded in skips. “Easy” I thought to myself, I can just use a pick and shovel. As luck would have it a local craftsman Eilir Rowlands was next door doing some stone work. He agreed to do the excavation for me with his mini digger and to face the outer wall of my pond in slate when we were ready. Apart from the speed at which Eilir dug the hole, the five enormous boulders that his mini-digger only just lifted out confirmed that we’d made the right decision to use mechanization.

Eilir and his mini-digger struggle with one of the boulders
Eilir and his mini-digger struggle with one of the boulders

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With most of the hole dug, we just up to me to finish off with a spade, and plan the location of the filter. I found it almost impossible to achieve smooth sides and base to the hole because of the slate chippings that were embedded in the clay soil. I was sufficiently worried about the liner being punctured to change my design to incorporate a 4 inch concrete base and extra underlay, which meant digging a little deeper and wider.

My son Patrick checking the pond depth as we finished the excavation by hand
My son Patrick checking the pond depth as we finished the excavation by hand

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Neil helped with the concreting the base and at the same time we installed the Bottom drain, 3“ pipe work, a concrete base for the Hydra 3000 filter (Japanese Water Gardens). We also completed the Block work around pond and the filter bay. Throughout the construction I received loads of help and advice from the North Wales Koi Society and Richard and Donna at Richdon Koi.

Neil busy constructing the Block work
Neil busy constructing the Block work

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During the summer of 2005 Eilir completed the Stone work around the outer wall of the pond and I started fitting the liner, but not before I’d covered the entire excavation with a layer of bubble wrap, sand on the concrete base and an impenetrable underlay. I was determined that nothing was going to damage the liner!

Bubble wrap, sand and underlay in place
Bubble wrap, sand and underlay in place.

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A local electrician fitted the RCD switches, water proof sockets and armored cabling to the 2 filter bays and pretty soon we were filling the pond for the first time and stretching the liner into shape. After making a few adjustments the stone work and capping stones around the edge needed to be cemented in place. More by luck than judgment I’d managed to get the liner to lay fairly flat with very few creases and quite neat folds by using special double sided tape. My waterfall took a few days to build using giant flag stones and one or two slates ‘liberated’ from up a local Welsh mountain

Yours truly fitting the liner
Yours truly fitting the liner

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I painted all of the waterfall and inner wall stonework with a couple of coats of clear G4, and when this was dry the water level was raised and the filters filled. My 1.5” pipe work went together well with no leaks or problems. The only slightly annoying thing was that my Aquamax 15,000 pump was too powerful for my system and I had to run it with the ball valve half closed to prevent the final chamber of the Hydra 3000 filter from being emptied. I’ve since swapped it for an Aquamax 10,000 which works a treat.

I left everything running for two weeks before introducing five homebred Kamikaze Koi, donated by Colin Jones (North Wales Koi Society). They sat it out throughout the winter helping to get my filters seeded. Then from March 2006 I gradually introduced a few ‘smallish’ Koi ranging from 3”-7”. Some of these I’d grown on in my 150 gallon indoor aquarium. I had a slight problem early on with parasites, probably due to inadequate quarantining. Several of my fish kept flicking on the bottom of the pond, including one of my favourites, George the Kohaku. North Wales Koi Society member, Ken Williams, took some scrapings but we could see nothing under his microscope. I eventually gave George a series of salt baths, and treated the pond twice with Malachite Green and Formalin. What ever the parasite was, the treatment worked and all the fish were back to normal very quickly.

Although the pond was functional and things were running fairly well with the water parameters behaving themselves, the garden around it looked like a building site. Finally in May 2006, I persuaded Neil to come back and together we completed the Decking and the feature that my wife Mags has nicknamed “The Bridge over the River Koi”. I also fitted a Shade sail to stop direct sunlight falling on the pond and to deter a very persistent Heron that has emptied 2 neighbour’s goldfish ponds. The landscaping around the pond involved 9 tons of Limestone chippings which all had to be shoveled and wheel barrowed by yours truly (talk about back breaking work). This gave the pond a slightly Japanese/Welsh feel which I think looks superb.

Shade sail and Bridge over the River Koi completed
Shade sail and Bridge over the River Koi completed.

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Two of the Boulders excavated from the hole take pride of place within the landscaping.

It’s taken far longer to complete the pond than I could have imagined, and I went over budget. But to say that I’m pleased with the result would be an understatement. Even though Mags complains about the amount of time I spend tinkering with the filters and generally watching the Koi, I think she likes the pond too (or at least the decking where she sunbathes quite frequently). I’m not going mad buying expensive Koi, preferring to buy low cost examples of many different varieties. With approximately 30 small fish at the moment, I will soon become over stocked as they grow. At that stage, I’ll find other homes for some of my Koi with friends and neighbours. I may even have to give away the original five Kamikazes who have survived my initial blunders and frequent over feeding.

Water fall return at one end of pond
Water fall return at one end of pond.

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Recently I’ve fitted a second hand Answer 250 in the Vortex, and the results are amazing. The water clarity was always pretty good, but now it’s unbelievable! I also replaced my brushes in chamber two with Kaldnes K3 and my Koi are thriving.

I like to unwind at the end of the day by just sitting at the edge of the pond watching the Koi cruising around and coming up to feed. I’ve fitted 3 underwater lights and some garden lights so I can view them after dark. I’d like to apologize to my poor wife and colleagues at work for the past 3 years and my constantly droning on about the pond, my Koi and how much my back ached after a weekend digging. I think it’s been worth it though.

What would I do differently next time? I’d use block work and fibre glass, install a window and also a heater. I’d also bench the pond floor more steeply to help solids get to the bottom drain easily.


More photos from Martin & Mags superb Koi pond, can be found in our Gallery »

Koi varieties

Kohaku, Showa, Asagi, Shusui, Chagoi, Ochiba Shigure, Doitsu Matsuba
Harawake, Kikusui, Ogon, Bekko, Grass carp, Sterlet

Pond Details
4500 gallons
Raised Firestone Rubber Liner.
Concrete base, Stone work around edges.
4 inch bottom drain, reduced to 3 inch pipe

Main Filter
Hydra 3000 filter ,Answer 250, Kaldnes K3+K1, Matting, Aquamax 10,000, TMC 55W UV

3 Returns
-Trickle Tower feeding Water Fall
-Small Vegitable filter
-1.5” pipe

Second Filter
4 inch pipe Skimmer
Vortex with Brushes
Aquamax 4000
Waterco Trimline canister filter
Return via Venturi

Martin & Mags Rocliffe

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  1. GALVIN April 17, 2008


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  3. Great page. I’m installing a shade sail over my pond right now, can you tell me how thick the poles were that you used?

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  5. Martin R August 8, 2010

    Hi, The Poles or post should be at least 2ft into concrete. The shade sails can generate tremendous force even in moderate breeze. Use galvanised Pad eyes, chains and turnbuckles from a DIY store or Scrwefix to secure the sail and get tension on it. I would also replace the metal rings in each corner of the sail with a shackle. This helps with connecting the chains, but also the metal rings do bend under tension.

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