Review on 2-in-1 pH and Temperature Monitor Tester Kit - 0~14 pH Measurement, Automatic Calibration, BNC Electrode Probe - Ideal for Hydroponics, Aquariums, Lab Testing, Drinking Water, Food pH, Saltwater/Seawater by Ryan Brunson

The PH probe only lasted about 5 minutes before going from 6.7 (where my tank actually is) to 8.63. Once it hit 8.63, it stayed there until I reset the counter. After a restart it works for about 5 minutes and then crashes again. I had this gauge installed for 3 days and calibrated it every day thinking the sensor was bad. This is not a probe; that's the meter itself. Disconnecting a probe doesn't change the reading if it fails that way. I will return this device as soon as possible. I had high hopes for this compact meter but unfortunately I have to advise people to look elsewhere. Edit: The seller informed me that this meter has a power saving feature. In the first 5 minutes, the meter measures every second. After 5 minutes, a measurement is required every 10 minutes to save battery power. This explains why I thought the readings were stuck, but doesn't explain why there is such a big difference in PH readings between constant mode and battery saver mode.