Inst464
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Viron e-Quilibirum Series Chlorinator Instructions V07-20
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8.0 Important Information about Chlorine Sensing by the e-Quilibrium
The Viron e-Quilibrium uses an ORP sensor to measure and control the chlorine levels in your swimming pool or
spa.
Before installing probes, balance pool water. Total Alkalinity (TA) must be 80 to 120 ppm, Calcium
Hardness should be 180 to 250 ppm, and pH must be between 7.2 and 7.6.
Dose pool with a small amount of chlorine before starting the e-Q. If no chlorine is sensed the e-Q
may go to fail safe mode and not start up. Some Chlorine should be present before starting the unit.
The Chlorine sensor will take 45 minutes or more to accurately sense the chlorine level in the pool.
Allow Pool pump to run for 45 minutes before attempting to calibrate the sensor to the pool water.
Confusion often exists about the difference and relationship between oxidization reduction potential (ORP) and
chlorine levels measured in parts per million (ppm).
Most pool shops and pool service technicians will focus on chlorine readings in ppm and not the ORP.
ORP is actually a more accurate and important reading than ppm because it measures the effectiveness of
chlorine and NOT the level of chlorine in the water. Relying on ppm can provide a false sense of security and
may even lead to use of a pool that is dangerous to swim in.
When chlorine is added to the water it reacts to form two separate chemicals, one is hypochlorus acid (HOCl) and
the other is hypochloric acid (HCl). The important chemical to form is HOCl as it is the active or effective form of
chlorine which oxidizes and disinfects the contaminants in the water.
The amount of HOCl and HCl formed depends on the pH of the water. The higher the pH, the less effective HOCl
is formed and the more ineffective HCl is formed. Ideally, a pH range of 7.2 to 7.6 forms the most HOCl while
maintaining soothing water to swim in.
At a pH of say 7.8, only 30% effective HOCI will be formed which means the chlorine is not being effective as
disinfecting the pool or spa water even though the ppm is 2 or 3 ppm.
However, at a pH of 7.2, a massive 80% effective HOCl will be formed meaning the chlorine is highly effective as
disinfecting the water even at levels of 1ppm.
ORP remains the best method to measure the sanitiser
’s (chlorine’s) effectiveness in the water. At a reading of
750mv a virus kill time is as low as one second!
Various other chemicals added to the water can affect the ORP. For example, most pools will have cyanuric acid
added to the water which effectively slows down the reaction of the chlorine to make it last longer. However, the
slower reaction time of the chlorine lowers the ORP, hence the e-Quilibrium will add more chlorine to maintain the
ORP and keep your pool healthy and safe to swim in.
8.1 Chlorine Reading and Cyanuric Acid
Cyanuric Acid (CyA) is often recommended by or added to swimming pools to make the available chlorine last
longer. It is often called stabiliser or sunscreen. CyA bonds with chlorine ions which prevents the chlorine from
oxidizing bacteria and other contaminants. This effectively reduces the oxidization reduction potential (ORP) of
the chlorine in your pool.
Chlorine efficiency or activity is reduced even when low levels of CyA is present.
Total Alkalinity (TA) buffers pH or keeps the pH relatively stable. The pH of your pool water is crucial to making
your chlorine highly effective, even when the chlorine is present in low levels. Measuring and adjusting your TA on
a regular basis will help reduce acid consumption and help keep your pH level in check. Variable pH will also
create variable ORP readings with high pH meaning your e-Q Chlorinator will produce more chlorine to reach the
set point ORP level than it would otherwise need.
CyA (STABLISER) adds to the TA reading. If CyA levels of in excess of 50 ppm are present, it is good practice to
divide the CyA by 3 and subtract the result from the TA reading. Therefore, if CyA is 60, and TA is 200, subtract
20 (CyA 60/3) from 200 for a TA reading of 180.
