The ICO connected water analyser is an assistant to help you keep the water in your pool or spa healthy, clear and balanced. To do this, ICO is equipped with electronic sensors that continuously measure the main water parameters: temperature, pH and ORP. Salt versions are also equipped with a conductivity sensor. How do these sensors work in practice? What are the technical features that ensure their reliability? We explain the role and technology of each sensor.
As its name suggests, the pH sensor measures the pH of water, i.e. the acidity or alkalinity of the water. It is measured on a scale of 0 to 14, by measuring the voltage potential of a solution.
The pH sensor consists of two electrodes:
- A measuring electrode, also known as a glass electrode: This is contained in a special glass membrane, sensitive to hydrogen ions (H+), which generates a voltage proportional to the H+ concentration. When the pH of the water changes, the concentration of hydrogen ions on the surface of the glass ball also changes.
- A reference electrode: its wire is immersed in an electrolyte solution, potassium chloride (KCl), which is also used in the probe storage solution, with a known and stable voltage potential. It therefore provides a constant potential for comparison.
ICO measures the potential difference (voltage) between the measuring electrode and the reference electrode and converts it into a precise pH value.
Die in der Abbildung sichtbare Keramikverbindung ermöglicht den Kontakt zwischen der internen Referenzlösung und der zu messenden Lösung, in diesem Fall dem Wasser Ihres Schwimmbeckens oder Whirlpools, und erhält gleichzeitig die Stabilität der Referenzflüssigkeit.
The pH probe is fitted with a BNC connector for connection to the instrument's electronic board. This is a classic type of connector for measuring instruments. It ensures a reliable and easy connection between the probe and the analysis electronics, without any loss of signal, while allowing the probe to be replaced without completely dismantling the instrument.
The ORP (Oxidation-Reduction Potential) probe is used to measure the capacity of water to oxidise or reduce chemical substances. This capacity is directly linked to the activity of the disinfectant.
Like the pH sensor, the ORP sensor consists of 2 electrodes.
ICO measures the voltage between the measurement electrode and the reference electrode. This measurement in millivolts (mV) is used to determine the disinfectant capacity of the water, or in other words, the effectiveness of the treatment.
For disinfecting the water in a swimming pool or spa, an ideal range of 650 to 750 mV is recommended. This value may be lower if the pool is equipped with another disinfection device such as a UV lamp or ozonator.
The ceramic seal is also present on the ORP probe to ensure electrical contact between the reference solution and the water, while preserving the stability of the reference liquid.
The BNC connector on the ORP probe ensures compatibility and excellent signal transmission quality.
By measuring the electrical conductivity of the water, the conductivity probe enables ICO to determine the Total Dissolved Solids (TDS). This value reflects the quantity of minerals and salts dissolved in the water.
It is particularly useful for salt-treated pools, where the vast majority of dissolved solids correspond to the salt present in the water for electrolysis.
The conductivity probe is essential for salt disinfection to function, as it measures the salt concentration in the water.
The conductivity probe also contains two electrodes. These two electrodes are placed opposite each other at a known distance.
Unlike the pH and ORP probes, the TDS probe has no reference electrode. To measure the conductivity of the water, the electronic circuit applies an alternating current (AC) through the electrodes and measures the resistance between them.
The higher the concentration of dissolved solids, the higher the conductivity.
The conductivity probe also uses BNC connectors, ensuring compatibility and ease of connection with the ICO central unit.
In the ICO application, under Settings / ICO, the ‘Sensors’ section has been added. It allows you to group the different types of sensors declared and to adapt the device configuration according to the presence or absence of a conductivity sensor.
Caution: If you indicate that you do not have a conductivity probe when you do have one, you will no longer see the conductivity information and the ‘Out of water’ detection function will be disabled.
The probes in your ICO analyser are much more than just sensors: they are precision instruments that constantly monitor the chemical parameters of your pool or spa water. The probes in your ICO Pool or ICO Spa are designed to provide reliable, accurate and long-lasting measurements. However, as with any measuring device, it will be necessary to calibrate the probes regularly to check their accuracy. Understanding how they work can help you to better interpret the measurements and to better take care of it.