During pairing, a solid light on for about 5 seconds indicates a successful pairing operation.

During pairing, a slowly pulsing light means your sensor is looking for a Gro Hub to pair with.

If your sensor hasn't been paired yet, a rapidly blinking light for about 5 seconds means it couldn't find a Gro Hub to pair with.

If your sensor is already set up, a rapid blinking light means it's having trouble connecting to the Gro Hub, or that you just un-paired and reset your Sensor.