Does anyone know why this happens occasionally/randomly? Sometimes it's because bubbles get caught under the probe and I tap the probe a few times and it returns to the proper reading but other times there is no discernible reason. I woke up this morning and from 1am till the morning it went from a stable reading of around 36 up to 42. I tapped it out and it went up this time to 45. And yes, I double checked with refractometer, it's still dead on 35.