Wooden Decking for Koi Pond Filter

The wooden decking that covers the filter of my third pond is rotting! And they are only about 3 years old. I am not sure why this happens. I think it could be that the wood is not properly treated and painted. Also the prolonged rainy weather over the last year could have played a role. Another factor could be that the wood used is not Balau wood as specified.

The recommended wood material for making the Koi pond decking or any outdoor furniture in South East Asia would be the Chengal or the Balau wood. Chengal wood is better but more expensive, so I have agreed with my contractor to use Balau wood instead.

The wooden decking in my previous pond was much more durable. No signs of rotting even after two to three years in the sun and rain.  The material used for that pond decking was Chengal wood, AND the wood planks was painted with Hickson paint before and after installation AND held together using stainless steel nails.

I am going to make sure that my new filter decking is done properly this time….if and when I replace it in the future.

Water Lilies

  With the strong sunlight and regular fertilising, my lilies are thriving and blooming.  Lilies spread out in a circular fashion from their rooting point or pot. My current lily pond which measures 4m x 1.2m is considered too small and small leaves are actually sticking out from the sides of the pond

I have two varieties in my pond.

This is a large flower, each petal measuring about 60 cm. It opens up nicely under strong sunlight and closes up when it gets shady or cloudy.

This variety flowers almost non-stop. Buds are constantly pushing up from under the water. You get one flower per day. The flower is about half the size of the other variety but the colours are more vivid.

Kingfisher

This guy has been visiting my garden, waiting to pounce on my comets and baby kois in my lily pond. I don’t mind losing a few comets to keep their population in check, but please, not my baby Koi.

Good start in the Year of the Tiger

The weather was HOT HOT HOT in the last two weeks leading to the Lunar New Year in Singapore. In preparation for the new year, I did my usual pond filter maintenance, trim and re-potted some young water lilies and added fertilisers too.

My Koi looks great, the pond water is clear and my water lilies are blooming again! All ready for the festive occasion.

In the tradition of the Lunar New Year, the last weekend has been busy with the visits to relatives and vice versa. One good thing about having a Koi pond in the house is that my young nephews and nieces are actually looking forward to visiting Uncle Jeff so that they can feed his fishes.

A Koi pond or water in the house is good for feng shui and brings luck to the occupiers. Good Feng Shui or not, I made some money on the Gin Rummy table as well. Good start in the Year of the Tiger.

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.

Help! Water is overflowing from the pond

I got a call  from wife today to say that it is raining and water in my Koi pond is overflowing over the top and is seeping into the adjacent room. As I am in Hong Kong, I could not check why this happens. As she is not familiar with the operation of the drain pumps, the solution is to bail out the water by hand.

Later I heard that the North East monsoon has hit Singapore and a lot of rain has fallen. The evening news showed flooding in some parts of Singapore. I suspect the overflow pipe in my pond is probably too small to handle the sudden heavy downpour of rain. The 50mm diameter pipe, that works in normal situation to maintain the maximum water level, just could not handle the super heavy downpour today.

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.

Plants for Koi Pond – Water Lily

I have attempted to grow water lilies in my Koi pond since the early days in my first pond. In my first pond, I placed my water lilies in the shallow garden pond that overflows into the main Koi pond. That way, my large Koi will not be able to get to the leaves. Unfortunately, my shallow garden pond was near the water fall and I found that the constant flow of water is not good for the plant. After some time, the plant just deteriorated and died. I found that that the water lily is best grown in warm, still water and with plenty of sunlight.

   Pictures of my water lily in my first pond. Other aquatic plants in the picture includes the Umbrella Plant, floating water lettuce and penny wort.

In my third pond, I have better results with the water lilies. Again, I grow them in pots placed in a separate pond with only a few small Koi in it. This garden pond is physically separated from the main Koi pond with the larger Koi but share the same biological filter system. Water flow into the garden pond from the filter return pump is adjusted to be slow enough to maintain water circulation but not fast enough to disturb the floating leaves of the water lilies. Besides maintaining a slow water flow, I also found that regular fertilising and plenty of sunlight helps to maintain the blooming and plant growth.  2 to 3 Fertiliser tablets are pushed into the soil in each pot every month.

    Pictures of the water lilies blooming in my third pond. As the old flower fades away under the water, a new flower head will appear to replace it.

Plants for Koi Pond – Umbrella Plant

The Umbrella Plant (Cyperus Alternifolius) is a rush-like aquatic plant with foliage arranged on stems like the ribs of an umbrella. It originates from Madagascar and is very easy to grow under the hot, sunny climate of South East Asia. Unlike the small dwarf papyrus, this plant can grow up to 5 feet or more in height. As this is a large plant, grow this plant in a large pot that can be fully submerged or half submerged in the pond.

The photo shows the umbrella plant growing well in my third pond.

As new leaves appear, the older, longer leaves will tend to droop. I cut the older leaves away to keep the plant growth in check. The roots may grow out from under the pot and spread freely in the water. The plant’s roots actually split the clay pot it was grown in after a few years of growth in my first pond. When this happened, I threw away most of the old growth and kept the younger plants after dividing them from the massive root ball using a knife. The new young plants are replanted in a new pots with pea gravel or soil and they grow easily.

Biological Filter Maintenance

I flush my biological filter system regularly (weekly) as part of the partial water changing routine but in terms of a real good cleaning, it would be once a year or even longer sometimes. What triggers me to do it?

Well, I usually do this when I noticed that the water level in the return pump chamber falls below the usual level. My filter system consist of several chambers and uses gravity to move the water from the first chamber (with the inlet from the pond) to the last chamber where the return pumps pushes the water back to the pond. A fall in the water level in the return pump chamber signifies that there is some “resistance” to the water flow within the filter system. This is normally caused by clogging of the biological filter mats and/or the cockles shells and crushed coral chips I used for PH buffering and biological filtration. Hence a more thorough back-flushing or good cleaning of the biological filter is needed.

Cleaning Steps

1. Stop the return pumps. 

2. Insert the standpipes to stop the pond water from going into the filter. Note: as I am using venturi pipes, the water could backflow into the filter through them until the pond water level reaches the level of the venturi pipe. In any case, the venturi pipes are about 4 to 6 inches below the normal pond water level.

  Picture showing the Standpipes in the filter chamber. Some are not inserted yet. Sockets for the standpipes can be seen at the bottom and water comes into the filter from the pond’s bottom drains through them.

3. Open the specific ball valve in the sludge chamber for the selected filter chamber.  Water will reverse flow down the chamber through the bottom drain in the selected filter chamber and goes into the Sludge chamber. This is known as back-flushing the filter.

  Picture showing the ball valves in the Sludge chamber. Drain pump comes with automatic cut-off system that stops the pump once the chamber is empty of water.

4. Turn on the Drain Pump in the Sludge chamber to empty the Sludge chamber. 

4.  If I am cleaning the filter mats, I would not remove them from the chamber since they are placed vertically and I could clean them with a hose. I would just hose them down with water and drain the dirty water out through the bottom drain in the filter. Theoretically, tap water should not be used since tap water contains chlorine and chlorine kill bacteria in the filter mats. Best is to use pond water but I have been using tap water without any major consequences. The trick is not to over-clean the filter mats until they look brand new again! You still need the denitrifying bacteria for biological filtration. Instead, just give them a good flush and leave some brownish “dirt” behind. These “dirt” are the bacteria and they will soon multiply and colonise new bacteria when the filter system is put back into operation.

5. If I am cleaning my crushed coral chips and cockles shells, I will remove about half of them from the filter chamber so that I am able to clean the media at the bottom of the chamber. Placing them in sacks, made from nylon nettings, help facilitates removal from the chamber.  The removed sacks are hosed down with tap water.  I will hose them down the remaining sacks in the filter chamber (with tap water, of course!) and then drain the water out through the bottom drain.

6. I do not clean all the chambers at one go. Cleaning may affect the effectiveness of the biological filtration until the bacteria has time to grow and settle. I usually flush 2 out of 3 of my biological filter chambers, leaving one chamber for the next time. This will avoid a potential for a nitrite and ammonia spike in the pond due to lower level of biological filtration after the filter cleaning.

7. After cleaning, I remove the standpipes, one at a time. I will see a big gush of water from the pond into the empty filter. This is good as it flushes the pond’s bottom drain pipes leading into the filter system and removes the muck that has settled at the bottom drain pipes. Have to reinsert in the standpipes before the water in the first chamber overflow into the second chamber.  Do not want this muck to go into the cleaned filter. Now is the time to flush out the first chamber (standpipe chamber or settlement chamber). I repeat step 7 until clean water is coming into the filter from the pond, i.e. pond’s bottom drains are cleared.

8. Close all ball valves in the sledge chamber and turn off the drain pump. My drain pump has an auto cut-off that stops the pump once the sludge chamber is empty.

9. Refill the pond. Add dechlorinator to your tap water if you are refilling a high percentage of pond water using tap water.

10. Turn on the return pumps once the water level is high enough for the filter to operate.

The whole cleaning process takes about an hour and is a good workout. Cleaning the filter media could be quite messy, especially if you have to remove them from the chambers. Wear protective rubber gloves if you cannot handle muck.

Filtration System for my Third Pond

My current pond consists of a main Koi pond, a water feature that overflows into the Koi pond and a physically separated garden pond that shares the same filtration system. The drawing below describes the filtration system and I would recommend this as a minimum design to anyone who is thinking of building a new Koi pond. This design overcomes a few problems that I encountered with the earlier filtration systems used for my first two ponds.

The drawing below shows the plan view of the filter.

The first chamber is the gravity pipe chamber or settlement chamber. Water enters the settlement chamber at the bottom from the pond's bottom drains through two 4 inch diameter (100 mm diameter) pipes. Two other lead-in pipes (75 mm diameter) pull water from my water garden pond and also from the bottom drain of my water feature. There is also a small skimmer pipe (75 mm diameter) that removes surface debris from the Koi pond to the filter. The settlement chamber allows for solid waste to settle before going into the filter media.

Each inlet pipe in this chamber is configured with a socket to allow me to push in standpipes to stop water flowing into the filter during filter maintenance. Photo above shows two standpipes in position.

A copper pipe with a tap allows easy refills from the water mains without the need to pull a garden hose. It comes with a float valve (commonly used in cistern) that automatically shuts off the tap water flow when the desired water level is reached. This chamber also contains a 50 mm diameter overflow pipe that leads to a drain.

Filtration Chamber 1 is for mechanical filtration. It contains filter brushes which acts as the mechanical filter. The brushes trap solid wastes and debris like fallen leaves. This can then be removed and hosed down when needed.

Filtration Chamber 2 is for biological filtration. It contains filter mats, placed vertically and supported by plastic grating at the bottom. The mats provide the areas for the bacteria to grow.

Filtration Chamber 3 and 4 is for biological filtration. It contains sacks of crushed cockle shells and coral chips, supported by plastic grating at the bottom of the filter chambers. The shells and coral chips provide the pH buffer needed to control the pH level in the pond. It also provides the areas for the bacteria needed in biological filtration to grow.

The Return Pump Chamber contains two return pumps. The pumps pushed the filtered water back to the Koi pond and water garden. One return pipe goes to my water feature and water garden. The other pushes water out through 3 venturi pipes into my Koi pond. The water feature and venturi pipes provide aeration for the pond. Once water is pushed out from the Return Pump chamber, gravity will draw water from the pond's bottom drains into the first chamber.

Each filter chamber has a bottom drain that leads to the Sludge Chamber through a 40 mm diameter pipe. Ball valves are used to open and close the bottom drains.

A long PVC pipe, with tailored ends as shown, allows the valves to be operated easily from above and makes filter maintenance easy. I can flush the bottom of all my filter chambers, especially the settlement chamber, within a few minutes. This makes the task so easy that I can do this almost daily.

The filter shell is made of thick reinforced concrete, as is the rest of my pond. Pre-casted, one-inch thick concrete slabs are used to construct the filter chambers. Balau wood is used for the removable covers.

Pond Location – My Third Pond

I have the opportunity to built my current and third Koi pond when I sold my corner terrace house and bought a 10-year old detached house in early 2007. I bought the house with the intention to extend the building structure to create additional bedrooms and living space for my family and of course, a new Koi pond!

The plot of land for the house is a longish, rectangular shape, 10m x 50m in size. I have appreciated the benefits of locating the koi pond close to the living areas of the house from my second pond. Hence this is a key consideration in the design of the layout  for the new building and location and shape for my new Koi pond.

We decided to locate the new pond next to my dining room and have it integrated into the building structure. This means the pond design has to be practically rectangular or squarish in shape, i.e. a formal pond.

 

The dining room is designed with glass folding doors on one side and glass sliding doors on another side which can be opened to bring the “outdoors” into the house. A water feature is constructed next to the dining room. It serves as a water return from the filter. Water from the return pump located in the filter comes out of a venturi pipe and also a large brown pot. Water coming out the pot signifies “overflowing abundance” which is a good feng-shui feature. It also provides the soothing sound of trickling water. For the koi, it provides the needed aeration.

A wooden bridge is laid over the pond to link the Dining room to a new “Entertainment room” on the other side of the pond. The pond circles around the Entertainment room. This creates the illusion that the Entertainment room is “floating” on the pond or some may say sunken into the pond.

 

My water garden is at the back of the house, and can be viewed from the Entertainment room. It houses some small Koi and water lilies. This part of the pond (water garden) is physically separated from the main Koi pond, although they share the same biological filter. Large Koi eats water lily and will tends to dig at the soil and muddied the water!