Modifying the Super Siphon for drawdown distances between 190mm & 720mm
The Super Siphon comes standard with a 400mm drawdown distance (+/- 10mm). That drawdown can be reduced to as little as 190mm by modifying the siphon in the field using the following procedure.
As supplied the Super Siphon has a 400mm drawdown. This 400mm is measured from the bottom of the inlet tube below the bell.
To shorten the drawdown stroke, subtract the desired drawdown distance + 5mm from 400 and drill a 10mm diameter hole in the side of the inlet tube or bell the calculated distance up from the bottom of the inlet.
As an example, if you want a 350mm drawdown
350mm + 5mm = 355mm
400mm - 355mm = 45mm
Measure up from the bottom of the inlet tube 45mm and drill a 10mm diameter hole.
When the hole is uncovered as the water level falls during dosing the siphon suction will be broken and the flow will stop at this point re-setting the siphon for the next dose.