Hmm. A Koi pond for us all to aim at ...

When we got the call about a pond that needed renovation we had to confess that this seemed to be... well... sigh.. yet another disastrous pond in need of massive financial injection and energy. It's nice to be one of the 'go to' companies when it comes to giving options and opinions on filtration though so we toddled along to take a closer look.

And so it started. A typical flat bottomed pond. About a metre deep. Odd shaped. No bottom drains. We guess this pond size to be about 25 to 30 kl.

There is only a few mm of water in the pond at this stage. On the right hand side is a thatched entertainment area

A difficult corner that presents a potential 'dead spot'.

Now the complexity starts. This pond is in fact the second of two ponds. This is the spillover feed to the pond from the upper pond.

This is the spillway of from the upper pond. The tree in the middle is an island.

Here we can see the spillway and the thatched entertainment area.

This is a shot from the spillway that shows the pond and the thatched entertainment area.

This is the upper pond with the 'island tree' showing where the water overflows from this pond into the lower pond. This pond is enormous!

This is a shot from the 'island tree' looking over the upper pond. This pond is about 12m by 6m - or around 50kl... Also completely flat bottomed. So now we have close on 100kl of flat bottomed pond to filter... This just gets better and better by the minute...

As is so often the case with Koi ponds there is always more to these things than meets the eye. We've given you a visual clue - see if you can spot it in the pictures above...

Here it is: Hang on a minute - just what is this?

On closer inspection, THAT happens to be this:

These are 160mm pipes. The small pipes above them are in fact 50mm pipes that act as venturis.

Now even for 100kl this looks a little extreme. And as it happens, there is a very good reason for these pipes... We haven't been entirely forthcoming about this system!

This is the reason for those massive pipes....

This is the rest of the pond! The two 'small' ponds we've shown you are the header tanks for a water feature pond the likes of which we have never seen in a private residence, anywhere. We doubt very much if there is anything to rival the sheer scale of this 'pond' anywhere in South Africa. This shot is about 20m above the pond and was taken from the lip of the second spill over pond that feeds the main waterfall.

Another shot of the same thing. The system comprises of a massive rock feature system that sports small islands and stepping stone walking pathways in the pond itself. There are a few large pools of water that are all interconnected allowing Koi to meander through the system at will.

This is a shot from ground zero showing one of the three bigger regions within the whole system. Every where you see rock you see a water fall...

Our camera lens simply isn't wide enough to encompass the whole pond. In the middle you can just about make out the thatched entertainment area. Yes, the whole thing really is that big!

This is a shot of the main waterfall from the ground looking up at the thatched entertainment area. At the bottom right you can see the suction inlets for the pumps that feed this monster. There are 3 5.5kW pumps and an 11 kW pump that deliver rivers of water to all the various streams and waterfalls that dominate the pond. We counted at least 11.

This is the first pond we showed you. The covered up pipes in the corner of the pond are actually 160mm diameter feeds that siphon off water to feed the water falls on the far side of the pond.

This is the main waterfall path

And this is a shot of the main waterfall from the upper pond feeder system as it heads downwards to the main system.

One of the bigger pools, again surrounded by more waterfalls...

The same pool showing the waterfall system - in this section alone there are at least 3.

All in all our best estimates are around 600kl of water, and around 2 million litres of concrete for the water feature! It is quite simply the most ambitious Koi pond we have ever encountered.

There are 5 x 110mm bottom drains dotted about in the pond that are primarily used for draining the system.

And before these pictures were taken the Koi pond was, yes, full of Koi.

We caught all of these fish and moved them to a mud dam for safe keeping. The pond had not been run for an unknown number of years - our best guess would be 20 - and there was sludge, muck and foul smelling rotting debris that lay on the bottom of the pond - in fact there was more of this muck than there was water.

The Koi population was self sustaining out of necessity. There were few large Koi and the vast majority of them probably bred in the pond. Catching them all with drag nets and the like was impossible. We drained the pond as far as we could, which took the better part of two days. Following this we netted the Koi and popped them into 3m holding porta ponds.

We managed this by stirring up some of the muck at the bottom of the pond - which was simple enough. 5 minutes later with all the oxygen stripped out of the water the Koi floated to the top and we netted them and dumped them into the holding ponds for recovery. They were then bagged and transported - and we managed not to lose a single Koi in the process.

As for the filtration on this pond, well, sadly after a long story the pond never was done. The house was auctioned and as far as we know the new owner was in the process of demolishing the structure.