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Hand-held Meters

By on May 18, 2009

This is a question from one of our customers posted for the information of all.


Hello Peaceful Crew
I am wanting to purchase a hand-held meter. My issue is to get the Hanna Combo or the Oakton ph meter.

Can you tell me what EC’s are? And how is knowing TDS helpful? And then is there something else to know to be able to use these two soil characteristics?

Do both meters require reagents?

Thanks for anything you can share with us.


EC measures the electronic conductivity of a material.  When testing soils,  high clay content, higher moisture levels, increased salinity and higher Cation Exchange Capacity all result in better conductivity and therefore higher EC readings.

TDS (total dissolved solids)  This basically measures everything in the water besides the water itself.  It is a good way to measure salinity in a sample.
With many organic fertilizers, a lot of nutrients are bound up in carbon compounds, so they are not very conductive.  The majority of the TDS load is from the sample’s ionic components.  The main ionic load is from four negative ions (bicarbonate, carbonate, chloride and sulfate) and four positive ions (calcium, magnesium, sodium and potassium).

Both meters will require reagents to calibrate the meters.  The 7.0 pH reference solution is a bare minimum, but using both the 7.0 and the 4.0 is much more accurate.  If you get the combo unit, you also need the ERGS reference solution.

I hope this helps,

Mark Fenton
Peaceful Valley Farm Supply

  Comments (4)


Do you have to use the reagent every time you use the oakton meter or just the first time you use it?

Thanks for your help.

Posted by Bob Irwin on Mar. 09, 2013 at 7:30:31 AM

Bob, The manufacturer recommends that you test the calibration on the meter each day you use it.

Posted by on Mar. 13, 2013 at 3:22:48 PM


Do both the Hanna Combo and the Oakton ph meter require that the soil sample to be tested be dissolved in distilled water in order to test the ph of the soil sample?  Do you sell any hand held instruments that test for soil ph that can be inserted directly into the soil, and, if so, how accurate are the ph reading of such direct insertion instruments compared with the ones that require the soil sample to be dissolved in distilled water solution?  Thank you.

Posted by Charles S. Sherman on Aug. 04, 2013 at 5:28:39 AM

Charles, Both the Hannah Combo and Oakton pH meters require soil to be dissolved in distilled water. We don’t carry any pH probe that just gets inserted in to the soil.

Posted by on Aug. 05, 2013 at 4:46:01 PM

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