Building a Koi pond does NOT have to be a difficult project. They really are quite simple to build.
With the technology now on the market, pond filtration has been made much smaller than its predecessors and they have become far more efficient and easy to install than ever before.
It’s the old cliché which is used in every industry the world over. ‘Do it once, do it right’ I can imagine a lot of people reading this article who are now on their 3/4th pond project and wishing they had done it the first time.
Research is the key to building a good pond. We now have a wealth of knowledge coming from the Internet and magazine’s…but most importantly your local Koi dealer. See what they are using on their own systems. After all the health of the fish and quality of the water is their most important business tool.
I am not going to preach to you on what filter you should buy or which is the best filter on the market. There are many designs all which will do a job, it’s just some will do it better than others. Its no great secret when you look at what I use at UKNishikigoi are all Nexus filters.
The most important thing when building a new pond is a bottom drain. It’s so easy to add one when you build a pond, and it’s vital to your Koi pond. In fact your bottom drain is as important as the type of filter you will add to the system. Just step back and think about it. If you have a pond and you ‘bench’ the base of the pond so everything falls into one spot in the middle, it makes sense to have a drain there to take away all the debris. This way there are no pipes or pumps in the pond, Koi will find anything in there to rub against which will cause damage. Using the bottom drain will make your pond into a gravity system which means the water level in the filter will be the same as the water level in the pond, when you attach a pump to the outlet on the filter to pump water back then this will cause the pull through the bottom drain, which means the force on the external pump will pull all the debris from the pond floor into the filter where it belongs.
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A pump fed system could not achieve this. The pump would be at one side of the pond and debris can settle on the other side of the pond because there are no falls on the base of the pond. A lot of people also raise the pumps in the pond. A ‘gravity’ system would mean the bottom of the pond would always be clear of debris, which would mean nowhere for any bad bacteria to live and go onto cause greater problems in the future. There would never be a need for a pond vac either; the maintenance saved by having a gravity system is massive.
Common sense will prevail in the filtration situation. If it looks too good to be true then take my word for it, it is. A small black header tank filled with a few pieces of chopped up pipe or hair rollers in an onion bag really isn’t going to filter your 2000gallon pond. It’s just impossible.
I appreciate that modern filtration can be very expensive. Add on the water pumps, Air pumps, Ultra Violet UV’s, pipe work and fittings, Heaters etc. I also appreciate by being in the business for over 15 years that customers can be VERY impatient and want the ponds finished as soon as possible which will cause corners to be cut. My advice is to sit down, research and wait until your budget can afford the right system. Of course many things can be added on at a later date but get the basics right and the rest will follow. If you cannot get the heating then make sure you have altered your pipe work so that you can add heating in the future with ease and speed. Put in a skimmer which cost very little and valve it so you can add the pump later. Just think about the system really.
The correct filtration unit is only as good as the media which is used. Again there are many on the market which can be used. Some ‘complete’ systems will come with media included. These are the systems I would advise buying. The main priority on a filtration system is to have as little ‘muck’ as possible. A good mechanical filter is vital to remove all large solids; this will then give the biological side of the filter the best chance to get the system mature. The bacteria are the most important ingredient. This will make sure your water is perfect which in turn means the Koi are perfect.
Mechanical filtration comes in many shapes and forms. Huge settlement chambers, vortex chambers, brush chambers etc have been used for many years now and have done the job they were designed to do. Modern day mechanical filtration has moved on. Gone are the days where we get covered in ‘muck’ each weekend by banging filthy filter brushes against the wall. Cleaning out big old settlement chambers and discolouring the water for days after. We now have such things as ‘pond sieves’ which consist of a stainless steel plate with 300 micron holes which your water passes over. They take all the large solids from your bottom drain and let clean water go straight through to the biological chamber of your filter, nothing could be easier. They can be cleaned in 30 seconds too!
These units will not only help achieve a perfect environment for your Koi they will also save on room in your filter area. There are many sieve type systems on the market today and as of writing they are fantastic and vital to a new Koi pond.
Speaking to other Koi keepers before starting the build will really help, the amount of mistakes will be really cut down (And we all make them no matter what level of experience we are at)
The exact same thing can be said about the actual dig. Something worth remembering is that the filter and pumps for a pond can be the same for a 2000gallon pond as a 7500gallon pond. The cost and everything can be the same. The increase in cost is on the actual hole and the finish.
With new products coming out all the time in the Koi industry it’s very important to research how to build the actual pond.
Liner is still a firm favourite within the fish keeping world, most outlets sell it, it’s easy to throw in, it can go on top of sand, and a bottom drain is easily installed through the liner. If you decide to go with this method then a ‘box welded’ liner is by far the best. These can be made to the exact measurements of your hole which will cause fewer creases in the liner. Creases are not really a good thing in a liner. In time bacteria can build up in folds along with debris that just gets stuck there and stays there.
Fibreglass is commonly used in the Koi Keeping world, in Europe anyway. This at the time of writing is in my opinion the best finish to have on a Koi pond, it’s very strong and its very smooth when applied correctly. Fish will not harm themselves on the finish. Pipe work can easily be covered in fibreglass making the pond a lot more aesthetically pleasing. There are no flanges with screws like you will get in a liner pond, the fibreglass just bonds to everything. The downside to fibreglass is not the cost. The actual materials are not that much more than buying a pond liner. It isn’t the application of the fibreglass either. It’s the horrible fumes that applying fibreglass gives off. It’s harmful and my advice is to get a professional to do the job for you. I know many people who now buy the materials and ask a professional to do the application saving costs along the way.
New products that are creeping into the main stream market are things like ‘Polyurea’ which is a spray on rubber. It is quite an amazing product and I see it making a huge impact within the industry. The simplicity of it is its major advantage over other methods. Sprayed on in a very quick time, takes minutes to actually set and water can be added straight away. This is a very strong and efficient way of coating your pond. At the moment though it is not widely used which means it can be quite expensive. I think it’s only a matt
er of time before more people start to use thus bringing the cost of making ponds with it very low.
Designing the system should be pretty easy to do. Mark out the shape of the area you plan to use, draw a diagram after marking it out and work out how deep you need it. A simple rule is length x width x depth x 6.23. This will then tell you how big the filter will need to be.
The shape of the pond is also very important; you need a shape which will give a good flow. Flow rates are really important for the fish’s growth and health. Even if you want a square pond make sure the edges are rounded off causing a smooth circular flow.
ALWAYS use the 1 drain to 1 filter rule. Do not try and pull through 2 drains, it just won’t be efficient. There are single filters on the market than will filter up to 7500Gallons with a single unit. Anything bigger than these then 2 drains is vital anyway. Flow rate through the filter will also come into play. A general rule of thumb is to turn the pond water through the filter once every 2 to 3 hours. Take a Nexus 300 for example; this filter will filter a maximum of 7500 gallons. You can put 2500 gallons per hour through the Nexus 300 giving you a turnover of 3 hours, perfect. Use the same guidelines for the filter you decide to use. Of course it’s always better to over filter rather than under filter.
Going back to how vital bottom drains are to a Koi pond system. Converting a currently pump fed system into a gravity system may not be all that hard to do. If you have a liner pond then installing a bottom drain is a very simple project. Most off the shelf bottom drains come with a flange and screws so a simple over lapping of the liner onto the drain then screwed down, I would also use some kind of sealant for extra safety. The liner can be easily lifted up and a trench can be dug for the pipe under the liner. The only major aspect is how to replace the filter and if it can be adapted to a gravity system. Altering concrete/fibreglass systems is much harder and major construction will be needed.
