UPDATE 17/05/10 to 19/05/10

The final pond base has been poured and a gentle slope of 30cms (12”) from the vertical walls to a 1.5m diameter (58”) flat central around the drain has been formed.

The drain top has been placed temporarily to check the fit between the stainless steel legs is perfect.

Nine pond wall return lines have been fitted all around the pond at 70cms (27”) below final water level and the three pond wall lights have been positioned.

The pond wall build continues.

The filter units, air pumps and skimmers are now on site and stored for the moment.

Final water levels in pond and filtration areas are checked by Theodolite.

A surface skimmer is being levelled and fixed into position.

Pipelines continue from pond to filter area.

These three 4” (110mm) tubes will each be split by a ‘tee’ and two 90 degree elbows to produce six filter feeds from the main drain.

As the pond walls continue so do the pipeline installations. This only shows the bottom drain lines and the 1.5” air supply line to the central diffuser. There will soon be eleven return lines in 2” (63mm) bore; two blue alkathene lines for the fountain; three 3” (90mm) supply lines from the surface skimmers before the trench can be back-filled.

All that will be seen when the courtyard is finished will be the circular pond itself. All other equipment will be concealed from view. Obviously this distance between pond and filtration system involves significant pipe runs.

The flow rate back to the pond from each of the six filter units is only a modest 1,550 gallons (7,000 litres) per hour but the extremely long return run, the fittings used in each line and the entry depth into the pond produces significant friction loss. We need to test several makes of water pump by clamp-on ultrasonic flow meter before making a final choice here.

Before the stone pond wall cappings can be fixed permanently to the pond walls, the entire pond needs to be rendered and the glass fibre lamination to the pond needs to be completed.