YINMIK pH Meter, Digital pH Tester for Hydroponics, pH Temp Meter with Horizontal Display for Pool, Spa, Hot Tub, Indoor Plants, Koi Ponds, Drinking Water, Wine Beer Making, Aquarium, Aquaculture

Great ! Even brought a spare as they work so well. Very accurate and easy to use. No need to spend a fortune, perfect at this price.

7 months it lasted, I needed to change my batteries-no biggy. Apart from it won't display any digits except 0.0000 and the temperature. It won't let me calibrate. I know it's only £20, but how many do you need to go through before you find something that's decent?

Went faulty after two months use requires a new probe

I needed a quick replacement when my other ph pen died. This pen filled the roll incredibly well. The included temperature gauge is an amazing value and seems relatively accurate. I have not tested the temperature against another meter. The other brilliant feature is the backlight display that auto shuts off after about 10 seconds. you can still see the reading, but the backlight turns off to save battery. accuracy - this pen, When tested against my Milwaukee ph pen shows a difference of only .1, this is without calibrating the YINMIK ph meter out of the box. reliability - used for only about a month so far without issue, will update if it fails. accidentally fully immersed the meter in water for 2-3 seconds. dried the exterior and it remains fully functional. support your local brands when you can, but this is a GREAT backup pen.

Edit: Great for the price! Despite what i originally thought, it does a great job at staying calibrated (holding strong for 1-3 months now). It contains everything you need to use it *except* the storage solution that protects the bulb - I think they should be more clear about that so you can purchase that too when you're ordering (but it looks like most brands don't include it when you purchase a meter). I'm also going to try one of their other meters in the near future.

The two devices were calibrated simultaneously, and then a pH test was performed on tap water; both devices gave the same result.

Easy to calibrate and easy to use. From what I can tell it is accurate but I have no way of measuring for certain.

I’ve not been this frustrated for a hot minute. I just spent the better part of two hours going back and forth calibrating and re calibrating this stupid pen trying to stabilize the readout and it just won’t work. It reads properly for the test liquids at first and then when I go to actually use it for something I NEED it for and what prompted the purchase to begin with- it DOES NOT WORK. The readouts are off by over 2 whole points nearly every time. Even just testing it to see if it was a fluke, I tried reading my distilled water and it’s telling me it’s at 4.9-5.8 when I know dang well it sits at a perfect 7.1 every time. This pen is utter garbage - unless I got a bad one? I dunno. This has been SO frustrating!