I hate to potentially be the bearer of bad news, but I just bought a very similar one a few months ago (delivered 12/23/16 per Amazon). The readings have always been suspect. Since the design is identical and just the color and name have been changed, these are probably manufactured by the same factory in China. So we don't know when each unit was manufactured or how they were treated during shipping. Your experience will hopefully be different from mine.
Three examples:
My water, per the county report and unreliably corroborated by another <$20 POS pH meter is around 8.1. This meter consistently shows it between 7.0 and 7.5. It shows distilled as something in the high 5s - low 6s. This is after the calibration and re-checking the calibration by testing the calibration solutions.
I have a Flander's Red acidifying, and while my notes indicate it going in the direction of more-sour, the pH has also been going up.
This past weekend, I took a reading of post-pasteurization Berliner Weisse and it showed a pH of 8.something (I did chill the sample). I figured the mash pH has to be around 5.3 (predicted using Bru'n Water). Really, it is extremely unlikely to have a post-mash pH over 6, so I threw the thing into the trash and ordered one of those $100+ ones. It gets delivered today.
I really hope your experience is better than mine.
PS: not trying to rip on China, I order a lot of geeky electronic stuff via eBay that comes from China and normally don't have problems. Seems pH meters are very different from the circuit boards and stuff I buy :-(
edit: formatting