The IntelliChlor tends to have problems with temperature compensation. I think that itís most likely due to an unreliable temperature sensor.
I think that the sensor tends to drift away from the true water temperature over time, in many cases. If the water temperature measurement is off, the salinity will be off as well with the salinity error being proportional to how inaccurate the temperature reading is.
If the sensor reading goes outside certain limits, the system will assume that the temperature sensor has failed and it will use 77 F as a default water temperature. In that case, the error will depend on how far the water temperature is from 77 F.
Part of the problem is that the Intellichlor does not report cell temperature, even with automation. If it did report cell temperature, one could detect and resolve problems quickly.