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Skimmers
- South African style
I live in a community where swimming pools are commonplace. They all have these skimmer boxes built into the wall but none of them are ever used as a skimming device.
When I was a child I can remember these wall mounted skimmer boxes had a hinged flap with a float on top. Water was pumped from inside the skimmer box (or weir as we call them) and the hinged flap ensured that only the very surface of the water was "skimmed" off.
In the last 30 years I have not seen a swimming pool working like this (and the way you are using them in koi ponds).
What happened was that somebody invented the automated pool cleaner ("KreepyKraully" or "Barracuda" amongst others) and the hose from these devices plugged into the weir. There was now no longer any surface water flow through the weir so we stopped calling them skimmer boxes.
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Here is what the setup usually looks like. |
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These automated pool cleaners were great for cleaning the bottom
of a swimming pool but floating debris needed a new solution as the
skimmer box has had it's function usurped. What has been developed are skimming devices that utilise some of the energy of the returning water jet coming back into the pool from a wall outlet. (Just like some of the energy of returning water has been utilised in koi ponds to entrain air in the familiar venturi returns.) |
| Skimming devices employing a similar venturi principle are everyday here and are very effective at skimming surface debris and depositing it into a mesh bag. | |
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This is a typical one. The round white body has an inner which
can slide up and down and ends in the doughnut shaped white float.
Only the surface water is pulled over this float. The blue bag is emptied periodically. It is surprising how rapidly it fills with fine floating debris as well as the obvious leaves etc. In the background you can see the automated pool cleaner on the end of its hose on the pool bottom. |
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Here is the exact same device in a koi pond where it is just as
effective. It was just attached to a near-surface return pipe that did not yet have a use. It has recently been disturbed so the some of the algae has come off leaving the obvious white very visible. It would be much more satisfactory if it was also made in black. |
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In this picture you get a better idea of just how effectively
it removes surface water. The fine mesh bag is too fine and readily clogs. It is frequently left off and the fine floating debris is "drowned" giving the pond that oily smooth look. However, when leaves are falling the bag is necessary. A bag of coarser black mesh would be preferable and easily made. 20% shade cloth works well. |
| The cost of this device here was less than equiv
of £20 UK. Something to think about..... Click on any image for a larger image |
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