Good Morfnoevight All you crazy stoners.
If your solutions are fresh and it will not calibrate it is time for replacement.
Even in humor the "N" word is just too inflammatory for me. I have not seen the show and I understand the setup now but it does not change my response.
You can use a soft tooth brush and clean running water. Unless your meter requires it a two point calibration of 4 -7 PH is all you need instead of three. simply run your calibration 7 then 4 then just retest the meter in the fluids if they have changed then recalibrate and test again if it still wanders it is time for a new probe. Since you are in soil PH is not going to change much even if you are a full point off from the target with watering. If you are having problems in your grow you need to look elsewhere.
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