Above you will see that we have marked out our pond which unfortunately means the loss of quite a nice tree ... but to try to work round such with its ever extending root system would be folly and probably lead to a disaster later on ... So here we have decided to remove the tree. The proposed filtration system will be housed in the rectangular area we are showing at the top right hand side, next to the waterfall/watercourse area and finally the pond itself .. If the site has a suitable access then an excavator can easily be used - and today there are many much smaller excavators available for hire and a pond as shown here could be excavated in a single weekend...
In Figure 2 below you will see that the top turf's have been removed to give a clearer indication of what we intend to place things ... and then if you are happy - start digging to the depth you intend your pond to be - in our drawing we are planning a pond with an overall depth of 7 ft 3" below the water level surface - but you do not have to have it that deep if you do not wish to - but again the principals remain the same ... The concrete base to the filter area should be a depth deep enough for the filters themselves to stand on with the finished water level as high in the filters as is possible when the pumps are switched off - so if you actual filters are, say 45"tall then the concrete base should be 45.5" - that will allow just 1/2" at the top of the filters themselves ...



 In this actual design for a customers pond  a 'Sump' was installed, as it was not possible, at the depth that was planned the pond and filtration area, to pipe direct into the sewer - this is often the case - so by creating a sump in which to discharge the waste water and debris from the filter system and from there it is pumped using a submersible pump up to the sewer level ... The sump is also best if it is concreted out at the same time as the bed of the filter areas are concreted out...


In figure 6 you will see the pipe work runs from the bottom drain sumps running to the filter area where a hole had been left for this purpose - make sure the pipe work actually goes through the wall of the filter house where it can be connected to later when you come to fit the filter system you are going to use... the wall to this area can be finished off later ....

  1. The walls of the and should be commenced for five courses only as follows:
  2. On straight runs use 18" x 9" x 4" solid concrete blocks and lay them on the 9" dimension to form a 9" thick wall.
  3. On curves use solid concrete common bricks and lay as illustrated below. The bottom drains are now ready to be sited as follows:-
  4. Mark a central line along the length of the pond base.
  5. Divide the line into three equal sections and then mark the centre of each section. This is where the centre of each drain sump is to be located.

Carefully mark out the pipeline runs from the drains to the point where they will start to rise vertically under the watercourse exit to the pond. Then glue a 90 degree bend to each line as required, next carefully glue the drain sumps to the other end of the tubes. At this stage, the tube from the sump of each drain should be totally horizontal but will be one inch above the pond base due to the depth of the drain sump. It is best here to pack under each drain line at 2 feet intervals, using 2" x 1" pieces of timber - this is to make sure that the pipe is perfectly horizontal and when you apply the second base of concrete to the pond that the concrete can flow under the pipe work and forms a solid bond. After you have done that then it is best to check these joints to make sure that they are perfectly watertight, so fill the pipe to the level of the sump top.. take it from us it is better to do this job now than it would be to try to trace a leak once the pond is finished .. at least you will have peace of mind knowing that any leak cannot be attributed to the bottom drain pipe work where it would be almost impossible to get at any leaking joint.


We are now at the stage where all pipe work runs must be made up and laid along the base of the waterfall/watercourse area. In this example they are as follows:-

  • Two 2" lines from each power skimmer (2 were fitted to this pond) - note the actual power skimmers cannot be sited until the walls are continued...
  • One 2" line from the heating system, this will exit in the and wall to give a 'clockwise' current to the pond water at 4 feet below water level.
  • One 2" line, a valved by-pass from the main filtration system pump, which can be used partially all the time and increased depending on waterfall requirements. This also should exit in the pond wall to also five a 'clockwise' current, this can be around 2 feet below water level.



All pipe work in the base of the waterfall/watercourse area has been encased into a concrete base and a gentle slope has been formed to the base which will take any debris into the pond and then to the bottom drain. The waterfall header tank has now been formed in concrete block in preparation for the final landscaping. Slopes have been formed tot he base of the pond walls and the pond base very gradually sloped to the perimeters of the drain sumps.


All filtration equipment and other items can be made up and installed in the filtration housing after feed and return pipe work has been installed behind the filter units as mentioned earlier.

This shows how to correctly install large rock work to this type of pond in order to give the effect of a natural 'rock pool'. It is important that rocks are selected that are large enough to give a correct effect to the size of the pond itself, and two thirds of the rock is actually under water. The majority of the weight is supported by the main pond wall as a proportion of the rock work is overhanging the vertical wall, even so the wall has to be reinforced as shown. Behind the rock work, a wall is incorporated that ends 1" above the water level, this cannot be detected once gravel landscaping is taken to the rock work.
On the opposite side of the pond a power skimmer is sited.

Prior to any rock work being sited, the whole structure should be completely finished and a 0.5" render applied to all internal surfaces, this should be mixed with a suitable fibre additive to add strength, after which a final 0.25" 'fine trowel finish' coat of render is applied. this is a task for an expert! After the render is completely dry, the entire surfaces of the pond should be checked by hand to see if everything is smooth to the touch.

When the pond has been checked for smoothness and everything is in order then waterproofing can be carried out as follows:-

•Ensure entire surfaces of structure are completely dry.
•Apply a single coat of P1 Pond Coating in your chosen colour to the entire surfaces, by brush and /or roller.
•When the first coat is dry then apply a second coating of P1

Note:- Neither concrete nor P1 will form a watertight seal to plastic drains or pipe work in view of this, after the P1 has been applied and has dried fully, seal these fine cracks with a film of non-toxic mastic or silicone sealant, this will do the job permanently.

After seven days you can then fill the pond to level with mains water, ensure that the three 4" slide valves/ball valves to the Vortex unit are closed. Check that the pond is watertight by leaving it full for a day or so.

Next, drop the pond level for approximately 2 feet by opening the waste discharge drain valve from the Vortex. Once the water level has dropped, close both valves.

Ensure that the rock work ledge is dried off, and the rock work can now be carefully bedded in mortar. The reason for leaving water in the pond at this stage is to reduce the risk of damage to the pond structure should an accident occur and a rock fall into the pond. Once all rock work has been positioned, the spaces between the rocks should be pointed as should the area behind the wall. All mortar should be given two / three coats of clear P2 SuperSeal after all mortar work is dry this is to seal in the lime...

The entire system should be emptied by pump and thoroughly rinsed with a hosepipe and then re-emptied in order to remove any un-cured mortar, pond coating residue etc.

After this, the pond can be filled via the mains water purification system; this unit should incorporate a flow meter and the exact start reading should be noted prior to starting to fill.

When full to overflow level, the water should be stopped and the final reading taken. By taking the first reading from the last reading, the figure will usually come out in 'tons/cubic meter's' of water; gallons can be obtained by multiplying the figure by 220 (gallons per ton/cubic meter)

At this point all the system should be checked for running operation very carefully:-

1.Ensure all control valves are in the 'open' position and all drainage valves in the 'closed' position.
2.Open fully the two control valves that supply water from the power skimmers, switch on skimmer pimp and check the 'pull' on each which should be the same, adjust by control valve if necessary.
3.Switch on the main pump that powers the filtration system and check running operation, ensure waterfall and by-pass can be regulated as required, check the flow of the current in the pond is visible.
4.Switch on central heating pump for heater circuit and gas heater, check system fires up. Adjust thermostat by hand and check operation is working correctly.
5.Ensure U/V system is operational.

Check all pipe work and fittings are leak free.

After two days, the system is ready for Koi stocks, but remember the system has to mature so a constant check on the ammonia / nitrite levels are very important.


The Finished pond, hopefully, should look something like this - although you can of course choose to landscape the area slightly different to this particular scheme ..

All the drawings shown on this page have been reproduced by kind permission of Peter Waddington and are taken from the Finest Koi publication ever produced - 'Koi Kichi'.