Pond Builder – Who should I engage to build my Koi pond?

Over the past few months, I have received several similar queries from my blog visitors who asked me for recommendations on pond building contractors.

In South East Asia, most Koi ponds are concrete ponds. For a concrete pond, it is best to engage a professional or experienced Koi pond builder.

Pond building is an art and it is good to engage a koi pond specialist rather than rely on building contractor who may be experienced with building water features or swimming pool but not a Koi pond. Koi pond has special requirements on depth, filter design and size, pumps to use, location of venturi pipes and bottom drains, aeration, shape, even special black paint for the sides of the pond (not tiles) ....just to name a few.

Also, once a concrete pond is built, correction is difficult to make without risk of leaks. It is good for the contractor to show you some reference sites.

My first two ponds were built by a pond-contractor that was a subcontractor to a landscaping contractor. Being new, I have to depend on a contractor who can show me references of past projects done. 

My third pond was built by a contractor who did also did the alternation and additions (A&A) works for my house.  Although I was happy with my earlier pond contractor, I choose this new contractor for my third pond because the pond is “integrated” into my building design and my builder happens to be also in the Koi pond building business. You can compared the filter designs for the 3 ponds and see that the designs are very similar but the filter for 3^rd pond is probably the best of them all since I do not have the space constraint that I faced with my first 2 ponds. I reviewed the pond and filter design for my third pond based on my experienced with my first 2 ponds and proposed design by the contractor is very close to what I had in mind.

At the end, you still need to engaged a contractor you can trust. Get them to show you the proposed design and it should have the features of a good filter and attractive pond layout to suit your personal needs.

Simple Surface Skimmer for Koi pond

Every pond ought to have a way to remove floating debris from the water surface. Dust, oil, protein scum, and small floating debris (insects, dead leaves) can be removed with a surface skimmer device.

The following picture shows the simple surface skimmer I used for my 3 ponds. I am using a gravity-fed filtration system. This skimmer pipe leads to the first chamber of my biological filter system. Alternatively, you may want to link this pipe to the second chamber to provide faster water flow since the water level in the second chamber is slightly lower than the first (due to gravity effects and water flow resistance between the first and second chamber).

 

The construction is simple. A 75 mm or 4 inch diameter PVC pipe that protrudes slightly above the water surface. Slots are cut to allow surface water to enter the pipe.  In my case, the slots are a little too big and my floating koi pellets are entering the skimmer through them. Hence I need to add a netting to solve this problem. Don’t make the same mistake. Cut narrower slots and have more of them around the pipe.

The skimmer is best located at a corner of the pond, near your filter. It would be best if you are also using venturi pipes for aeration and  have position your venturi pipes in such a way as to have water circulation around your pond.

Bats

This bat came to roost at the palm tree next to my pond. It will hang there in the day and goes out to feed at night.

Pond Location – My Second Pond

I have the opportunity to build my second pond when I purchased an old corner terrace house. As I was doing some A&A (Alterations and Additions) to my newly bought house, it gives me now the flexibility to include a pond into the overall plan.

The backyard in the new house is small, so no more backyard koi pond this time. Instead, my new corner terrace has space at the side and also a relatively large front yard.

We decided to locate the Koi pond at the side of the house, as close to the building as possible, so that we can enjoy the views of the Koi from the dining room (left of picture below). Large sliding doors at the dining room can be opened to bring us closer to our garden pond from the dining room.

View of Koi pond from the dining room.

The pond included a waterfall to provide oxygen for the Koi and to provide the soothing sound of cascading water for the humans. In the picture above, the waterfall is behind the large bird-nest fern and overgrown with money plants and pennywort. Feng Shui tip: The location and facing of the waterfall is such that the water must flow towards the house.

Building tip: If you are building your pond close to the house, I would suggest that you get an architect and/or qualified person (QP) to review the foundation of the house during the pond design and before the construction. Deep excavation close to the house may affect the building structure.

Lesson learnt from my first pond – filter design

Being my first pond and also due to space constraint, the design of my first pond filter has many shortcomings and areas for improvement. These are the lessons learnt and features which was incorporated into my second pond filter design and third pond filter design.

Separate Drain and Pump Chamber

My first pond’s filter (above) does not have a separate chamber to house my drain pump. I need to stop the pond water return pumps during maintenance and turn on the drain pump to remove water from the filter into the drain. That is not a big issue.

The bigger problem is with this: when I removed the 3 standpipes in my pump chamber to flush the dirt from the bottom of my filter, the waste water and dirt from the bottom of the filter chambers are mixed with the regular water in the pump chamber. I need to flush out all the water in the pump chamber before I can turn on the main pumps again. This makes the process of removing the waste from the bottom drains of the filter not efficient and unless I remove a substantial amount of water, some of the dirt are circulated back to the pond. Filter maintenance and water changes take about one hour.

A better design, which was used in the filter for my second and third pond, is to separate the drain/sludge chamber from the return pump chamber as shown below.

Instead of using standpipes, ball valves are used to open and close the bottom drains. The photo (actually from my current pond filter) below shows a sludge chamber with drain pump and ball valves in operation.

A long PVC pipe, with tailored ends as shown, allows the valves to be operated easily from above.

With this design, I can continue to operate my main return pumps while I extract waste water from the bottoms of the filter chambers. This facilitates easy and efficient partial water changes and clearing of the waste collected at the bottom of the filter chambers. It is so easy that which I can do this almost daily or at least weekly.

Need for mechanical filtration or settlement at the filter inlet

Due to space constrain in my backyard, my filter does not have many chambers. In the case of my first filter, my filter mats act as a mechanical filter in the first chamber. This means that the filter mats gets choked after a few months. The symptom is lowered water level in the pump chambers. When these happens, I will have to remove all the filter mats from the first chamber for cleaning, and thereby disturbing the bacteria essential for biological filtration. Quite a lot of work for me too. Not good. Unfortunately, the filter for my second pond did not provide for a mechanical filtration in the first chamber as well.

My third pond filter did! It has a chamber (photo below) to allow for solid waste to settle before going into the filter media. Visible at the bottom of the settling chamber are the inlet pipes from the pond’s bottom drains. Standpipes can be inserted into this inlets to close them off during filter maintenance.

After the settling chamber, the first stage of the filter provide mechanical filtration by using brushes. This is to trap solid wastes and debris like fallen leaves which can then be removed and hosed down when needed.