Dodgy pH meter alert
I have been using a pH meter of the kind commonly available in garden centres - it was a replacement for one that I wasn't sure was reliable.
It turns out that it's completely useless. I discovered today when I plunged the probe into a lemon, only to find that it read pH 8! I then tested it in 5% (0.5M) acetic acid (white vinegar) and it read pH 10. This is complete nonsense, of course! This may be a 'two off' experience, but the meter is obviously completely oddball. It does correctly read neutral values, but I wonder if both circuits are reading positive because of an electronic defect. Clearly, any corrective interventions I may have made if I'd relied on the meter would have been disastrous for my plants! |
Dodgy pH meter alert
On 8 June, 22:12, Homer Sparrow Homer.Sparrow.
wrote: I have been using a pH meter of the kind commonly available in garden centres - it was a replacement for one that I wasn't sure was reliable. It turns out that it's completely useless. *I discovered today when I plunged the probe into a lemon, only to find that it read pH 8! I then tested it in 5% (0.5M) *acetic acid (white vinegar) and it read pH 10. This is complete nonsense, of course! * This may be a 'two off' experience, but the meter is obviously completely oddball. *It does correctly read neutral values, but I wonder if both circuits are reading positive because of an electronic defect. * Clearly, any corrective interventions I may have made if I'd relied on the meter would have been disastrous for my plants! -- Homer Sparrow If you were a regular reader here you would have seen me posting about this problem a few times. If you are handy with a saldering iron then all you need to do is to open it up and swap the two wires around then it will read OK. David hill |
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As it happens, I'm very handy with a soldering iron :) However the unit is factory sealed in a way that makes it difficult to open without damaging it. Please can you post me a link to one or more of your previous posts on the subject? I'm also interested in electronics, btw. Thanks, |
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I can't believe these things were sold without having a basic check in the factory! |
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Thanks |
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