I noticed something strange when I got my Hanna salinity tester via amazon. The battery protector tab was missing, it just had a plastic ring in the device. Also there were black scrape points inside the tester like this, not my picture though.
I have no idea if it is used or a knock off but I know even after my continued calibration between it and the apex, I am now trusting the apex is right because it matched closer to my refractometer. Also look at the 1 star reviews on Amazon, it confirms this is happening.
I have no idea if it is used or a knock off but I know even after my continued calibration between it and the apex, I am now trusting the apex is right because it matched closer to my refractometer. Also look at the 1 star reviews on Amazon, it confirms this is happening.