Mike, I currently use a "pHep 3" made by Hanna Instruments. I just changed the batteries a week ago and once again realised that the battery cap which is opened by using a coin, is starting to be unworkable as the slot for the coin is sort of shredded; if you know what I mean. had this one for around 10 years, I think.
This unit is waterproof, meaning when you drop the unit into a solution, it doesn't self destruct. I destroyed my first two pHep pH meters by doing exactly that. Once they came out with the waterproof unit, I jumped at it. It has a temperature compensation factor built in, 0º to 50ºC. Calibration is relatively easy.
I just checked out the latest units, they appear to have a far better battery cover than my old unit.
https://hannainst.com.au/hi98107-phep-ph-tester
Mick.
This unit is waterproof, meaning when you drop the unit into a solution, it doesn't self destruct. I destroyed my first two pHep pH meters by doing exactly that. Once they came out with the waterproof unit, I jumped at it. It has a temperature compensation factor built in, 0º to 50ºC. Calibration is relatively easy.
I just checked out the latest units, they appear to have a far better battery cover than my old unit.
https://hannainst.com.au/hi98107-phep-ph-tester
Mick.