Why are the ICO measurements different from the strips?

Your ICO is programmed to measure pH, ORP (disinfection) and TDS (water conductivity). It is possible to observe differences in results between analyses carried out by ICO and those carried out with other instruments, such as test strips.

the chemical values sought by the two instruments are different.

the way the measurement is taken (depth, location or time of analysis) has also a strong impact on the result.

It is therefore not relevant to compare two tools that are not identical. The reliability of ICO measurements allows you to keep your water balanced for a long time and to preserve the equipment of your pool or spa.

What does ICO measure compared to strips?

Image showing a comparison of the connected water analyzer and test strips

pH measure

You can check the accuracy of your ICO's pH measurement by doing a comparative test with mineral water at home.

The disinfection level (ORP-Redox) versus the chlorine level

There are three different types of chlorine: ICO measures active chlorine. Most strips measure total or free chlorine which is not an indicator of water disinfection.

The ORP/Redox value determines the effectiveness of your disinfectant (bromine, chlorine). It is a more reliable indicator than the free or total chlorine level.

Image showing the differences between strips and ICOs. Presentation of their roles.

Diagram explaining the different chlorides that can be measured, by ICO or with a test strip.

Why can’t we compare chlorine levels and ORP?

It’s a common misunderstanding, but these two measures do not mean the same thing.

The chlorine level indicates the concentration of chlorine molecules in the water. It corresponds to the disinfecting power of the chlorine, which is affected by the pH and the stabiliser.
The ORP measures the effectiveness of disinfection
Example: when the chlorine level is just right at 2 mg/L, the pH rises to 8, but the ORP drops from 700 to 500 mV

Salinity

The ICO and the test strips measure the salinity of the water.

TAC and TH

The test strips estimate TAC and TH. Ideally, we would like the ICO to measure TAC and TH. Unfortunately, water chemistry has its technological and financial limitations. There are no consumer-grade electronic sensors capable of directly measuring TAC and TH on a continuous basis.

To measure the TAC, it is essential to carry out what is known as a titration by adding a chemical reagent.
To measure calcium, there are ion-selective electrodes available in laboratories; however, these are extremely expensive, very fragile and require calibration on an almost daily basis. They are therefore unsuitable for use in the harsh environment of swimming pool water.