HORIBALAQUAtwin pH-11 Pocket pH Meter Small Sample Amount min. 0.1mL for Soil, hydroponic, lab, Water, Aquarium, Food, Wine, Beer, Chemical

I am using the pH-11 to measure the pH values of natural water samples that are not buffered. So the pH values are expected to be variable. What matters is the general trend observed. And this little meter seems to be doing a good job. If you follow the instructions and watch a few of the videos posted by Horiba on YouTube, you should not have any trouble using these meters. Make sure you cover the entire bottom of the sample chamber (both the reference and the pH electrodes) with your sample. Also rinse the electrodes with your sample once before measuring its pH. I have asked a few technical questions by filling out the form on Horiba’s webpage and received helpful answers within a day.

Really like that the sample size can be very small, such as 0.5ml.And it comforting to know that this $130 pH meter agrees with the $20 pH meter I also own. :)

I loved it. Had to measure the ph values of bread & butter pickle relish.

Seems like a nice meter but the description on amazon does not disclose that this meter should not be used for ph below 3 (or above 9) so I had to return it. It also arrived with the electrode dried out.

The product was advertised as new but is not. It was slightly dirty and the plastic areas over the buttons is discolored. It gives an error message during calibration.

I tried to calibrate mine before using, and it calibrated 7.0 fine, then it automatically started calibrating the 4.01 point while the 7.0 fluid was still in there which screwed it up. I could not get it to recal the 7.0 sample. Then I switched to 4.01 fluid thinking I'll calibrate that and then redo 7.0 but then it started calibrating for 10.0 point, which this pH11 model is not supposed to be able to do at all, it's only a 2 point calibration model. It tried to calibrate 10.0 with 4.01 fluid and that apparently broke it. Instruction manual does not adequately explain how to calibrate. Now I just get Er4 message, means broken sensor. I never used it once. It never touched anything except 7.0 and 4.01 test fluids. New sensor $110.