I was surprised to see my chlorine level was ZERO when checking my chemicals. I checked the salt level and it was good. I opened up my Chlorinator controls and found that all of the signal LEDs (power, chlorine production, etc.) had gone out, but my digital display was still working. Googling this symptom led me to a frequently failing thermistor on the motherboard. I turned off the pool equipment with the switch panel, turned on the power to the chlorinator and found the thermistor. He lookedβ¦