I've brought one of those yellow cheap PH meters from Amazon and was wondering about calibration. You get 2 sachets of powder with it that appear to make up 2 different solutions. But the instructions just reference using one (the pH 7 ish powder) and calibrating with that. I'm assuming I use both?
Also, how often do you need to recalibrate, if it's often, I'm assuming I need to get a load of spare sachets from somewhere?
What do you folks do?
Also, how often do you need to recalibrate, if it's often, I'm assuming I need to get a load of spare sachets from somewhere?
What do you folks do?