The Atlas Scientific EZO™ pH circuit is a very sensitive device. This sensitivity is what gives
the pH circuit its accuracy. It also means that the pH circuit can read micro-voltages
bleeding into the water from unnatural sources such as pumps, solenoid valves, or other
probes/sensors.
When electrical noise interferes with the pH readings, it is common to see rapidly
fluctuating readings or readings that are pinned to 14 or 0. To verify that electrical noise is
causing inaccurate readings, place the pH probe in a cup of water by itself. The readings
should stabilize quickly, confirming that electrical noise was the issue.
Advice:
1. When reading pH along with other sensors, electrical isolation is strongly recommended.
2. Never build a commercial product without electrical isolation.