Hanna HI98107 Checker - Handheld Waterproof Pocket pH Tester with 0.1 Resolution pHep - Great for Aquariums, Pools, & Ponds.

Right now, it is working just fine. Seemed to calibrate easily and holding the pH reading pretty steady.

The manual is a disaster. It instructed me how to change the temperature from degrees Celsius to Fahrenheit, only to learn later that this less-expensive model doesn't support that. Also, the initial calibration procedure is confusing and leads to concern about doing it all properly. After all, all we want is to accurately measure, pH, right? I have a ~1,000 gallon pond with goldfish that I want to take care of. The water chemistry tests that I use have us compare the water color to a chart. The tests work very well but for pH it's almost impossible to be confident of the reading. Hence, I bought this meter. Thankfully there is ChatGPT, which step by step held my hand to set it up and take the measurement. I now believe that what I thought was a pH of 6.5 (with the color comparison system) which might be hurtful to the fish is actually 7.4, which is perfectly safe for them. So, I knocked a star off their review. If they have a product manager that person should either be let go or taught how to be a product manager. Having been one myself this is the kind of thing that one just does as a normal part of the career.

always bought hanna products. Not anymore. This pen stopped working about 3.5 months after i bought it. I tried cleaning and running calibration. NOTHING but ERROR MESSAGES!!