pH meter calibration

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agregory
Posts: 56
Joined: 01 Nov 2010, 13:19
Job Title: Lab Assistant
Suburb: Townsville
State/Location: QLD

pH meter calibration

Post by agregory »

Hi all,

Just wanting some advice. Biology soil testing EEI starts tomorrow. Brand new and hardly used pH meters were put in buffer solution 4 & 7 today. We had readings of 4.01-4.10 and 7.01-7.08. Is this acceptable? We (labbies) think so, but HOD thinks they need calibrating so that they all read the same and are spot on 4.0 and 7.0.

Opinions?
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fibreweb
Posts: 620
Joined: 20 Jul 2006, 10:00
School: Oxley High School
Suburb: Tamworth
State/Location: NSW

Re: pH meter calibration

Post by fibreweb »

It's High School biology!
In my estimation these calibration figures are quite adequate
The process is what is important and as part of the evaluation the possible sources of errors are discussed.
From my use of pH meters trying to calibrate closer can turn into a real headache.
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lada
Posts: 1024
Joined: 29 Jun 2006, 10:00
State/Location: NSW

Re: pH meter calibration

Post by lada »

Definitely good enough. How much closer does he want pH4 to be to 4.01?
Even after re-calibrating, you would be lucky to get it any closer.
Anyway, all students need to know, if the soil is acidic, basic or neutral
Lada
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Jazz
Posts: 468
Joined: 24 Jul 2006, 10:00
State/Location: NSW

Re: pH meter calibration

Post by Jazz »

We do not use "proper" pH meter for the soil. I bought this one in Bunning’s, cheap as chips. Measure; pH, moisture and light l. Less than 10 bucks
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Cheers Jazz
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smiley
Posts: 1398
Joined: 20 Nov 2006, 10:00
State/Location: QLD

Re: pH meter calibration

Post by smiley »

Same here Jazz. I'm not taking my precious pH meters and junking up the glass membranes with dirt!

In the same vein, I use a brick wall moisture meter (also from Bunnings) to test the soil, and that gives a workable reading too. :thumbup:
Cheers, K 8-)
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