I have three Hanna ph testers. Only one works calibrated.
The other two won't calibrate.
I need two testers working.
The one will calibrate 7 but not 4.
The other one will show 7 but then jump to 4 and fail both.
What is a reliable dependable way to test for 6.5 ph? Are there better products? What am I doing wrong?
I'm surprised to hear that about a Hanna product. My impression is that they were a "top tier" product, a la Bluelab.
If the meter is dropped on a hard surface, it could damage the glass probe. I speak from experience when I tell you that a rat can chew through the lead for the pH probe in the Bluelab Guardian monitor.
I bought the Bluelab "Growers Toolkit" in 2021 and I use both the EC and pH meters still, four years later. They both have a calibration reminder in the display. When it flashes, I go through the cal process and they're both always at least very close to dead accurate. They have always calibrated to spec when I hit the cal button.
If a pH probe isn't stored correctly, you may have to soak it in an appropriate solution for a day or so to get it working again. I do just two grows a year so I store my pH pen in a coffee mug of tap water that's at ~ 340ppm (which is why I have an RO unit!).
An alternative is to tap water is to use nutrient solution. I have Bluelab equipment that stays in my res so I had the blinding flash of the obvious that there's no need to use storage solution, rather you just need something that has some dissolved solids in it to keep the probe happy. I came to that conclusion because it's fine to leave a pH probe in a hydro res permanently so it would seem to make sense that it's OK to store it in a coffee cup with my tap water. Four years later, that seems to be the case.
Now that we have smart search engines, run this through chatGPT = "why does a pH probe have to be stored in a solution that has dissolved solids"
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