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HALO®pH and Gold Chlorine Sensors Installation and User Manual
3.2 Gold Chlorine ORP sensors
ORP (Oxidation Reduction Potential) is a measure
of the pool water’s ability to disinfect (sanitise) by
inactivating micro‑organisms and oxidising organic
materials. The Gold Chlorine ORP sensor senses the
ORP of the water and signals the Halo Chlorinator
to generate an appropriate amount of chlorine to
sanitise the pool water.
The chlorine level is displayed on the “Home” page,
in the centre of the screen, below the menu bar. The
level is shown as“Low”, “OK” or “High”.
When the filter pump is off, the ORP sensor doesn’t
take any measurements and the display will show the
last measurement as chlorine was XX. When the pump
has been running the ORP is displayed as chlorine is
XX. (New measurements aren’t displayed for 3 minutes
after the pump starts).
There are many factors that affect ORP readings such
as filter pump run time, pH, salt level and cyanuric
acid. Cyanuric acid suppresses the ORP (chlorine)
reading. Whilst many suppliers will recommend
up to 50 ppm of cyanuric acid (CyA), AstralPool®
recommends a maximum of 20 ppm cyanuric acid on
Halo Chlorinators (the lower the better, remembering
that fresh chlorine is produced everyday).
Generally, an ORP level of 700 is a good starting point.
When the pool is first installed, it is advisable to take
weekly measurements of free chlorine. If the free
chlorine level is too low, increase the ORP set point
(reduce the setpoint to reduce the free chlorine).
When making adjustments it is advisable to make
small changes (e.g. 700‑715) and then wait 2 or 3 days
before retesting the free chlorine.
It is also advisable to check that the filter pump
is running for enough time to allow for chlorine
generation. From the“Home”screen of the Halo
Chlorinator, press the “Settings” icon
generation. From the“Home”screen of the Halo
and then
press the “Stats” icon in the top ribbon to display the
“Stats” page. On this page the “% Cell Output” shows
the percentage of time that the cell is operating at full
capacity. If this figure is above 80%, it is advisable to
increase the filter pump run time. (Similarly, in the off
season, this figure can be used to allow you to reduce
the filter pump run time, however you also need
to allow enough time to filter out debris and skim
leaves, etc.)
The display of chlorine is “Low”, “OK” or “High” is based
on how far the ORP is from the setpoint, so the water
analysis could show that the free chlorine level is low
whilst the chlorinator is showing chlorine is OK, if this
is the case, the ORP setpoint should still be adjusted in
small steps as above.
Setting the ORP set point is done on the same page as
setting the pH set point. (See above.)
Halo pH and Gold Chlorine ORP sensors are powered
by a long‑life battery that should last 5 years. To
provide peace of mind, the battery level is indicated
via the Install page.
From the“Home” screen of the Halo Chlorinator, press
the settings Icon
From the“Home” screen of the Halo Chlorinator, press
and then press the “Install” icon
on the top ribbon to display the“Install” page. On the
lower left corner of the install page, press the “Add/
Remove”button and the ORP and/or sensors will be
displayed (along with other installed devices). In the
example below, the battery is shown with 2 “bars”.
At this stage, the battery life is approximately 1 year.
When the display shows 1 “bar”, the battery life is
approximately 1 month.
The graphic on the left side of the image is the signal
strength of the sensor.
