A high pond made of HD-PE - part 1

The plan

Our plan in brief.

• Rectangular high pond made of HDPE, internal dimensions 3.2x3.2x1.7m
• Walls stabilized with 76.1x3.65mm steel pipes in the PE struts
• Isolation: floor 6cm XPS, walls 20cm EPS completely welded in PE
• Biofilter, approx. 2,000l filled with Hel-X
• 1x floor drain 360mm with 160mm outlet and 1x skimmer 110mm
• Inazuma drum filter ITF drum filter - 80 septem, pump operated
• Pump: Oase Aquamax ECO Titanium 51000
• UVC: 110W Inazuma immersion lamp
• Heating: not yet define

What is the purpose of the pond?

In general, this is a question that should always be asked. We want the pond to perform many different tasks. On the one hand, we would like a pond in which fish can be kept growing, with warmth and plenty of food. In addition, Koi breeding is very important to us, so it is essential to keep the water level variable. This is the reason why a gravity system was not used. We therefore sacrifice a little energy and pump the water into the drum filter.

The drawing

If you want to start such a project, it often helps to draw it or to sketch it at a minimum.

In the drawing you can see the base plate in green and then the wall elements in blue and yellow. The idea is to first create the walls during production and then finish welding them onto the base plate. Also in yellow you can see the floor drain in the middle, which comes out on the right side with a 160mm pipe under the floor plate. Two pipes can be seen further up in the blue wall. This is an overflow and a skimmer in 110mm. The returns are made with two 110mm tubes. These are not visible in the above view.

Before the start of construction

As mentioned in our last article, we have also submitted a planning application here. So, if you are planning something like that, inquire whether you need a building permit.To ensure that everything runs smoothly during construction, all of the material, technology, etc. is ordered in good time so that everything is there when construction begins.

The start of construction

Among other things, 1186kg of HDPE were ordered in the form of sheets, pipes and welding wire. In addition, another 350kg of steel pipes to brace the walls.

In the picture you can see half of the plates ordered. With 2x4m in a stately size.

Immediately after delivery, it is the turn of the panels to be cut accordingly, the ribs for bracing and everything to be prepared as far as possible.

Here the panels are cut to size on the Striebig.

In addition, the holes for the steel pipes are made, which then ensure the corresponding stability of the walls in the struts.

After everything has been cut, it's time to weld the struts onto the walls. Of course, it is important to work precisely so that the steel pipes then also fit through all the ribs. With a diameter of 76.1mm and a bore of 80mm, there is not much leeway left with the usual distortion of the material due to thermal effects (e.g. welding). Precise work is therefore required.

In the picture above you can see a finished wall right after welding.

In addition to the PE welding work that takes place inside, things are progressing quickly outside.

The excavator starts excavating, a tree trunk gives way and shortly afterwards the formwork is already in place.

Everything is ready for concreting and before you know it, this is already done.

The floor drain sticks out of the concrete a bit here, as it is still insulated with 60mm XPS and an edge is also required to weld. The edge is then planed down after welding.

Here you can see the insulation glued to the base plate. The stones and barrels serve as weight immediately after gluing.

At this point we would like to thank Stefan Schraner from Schrani Koi, who supports the project around the PE work with advice and action.

Soon it will continue with part 2.

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Your koikichi.ch team.