North American Fruit Explorers mailing list at ibiblio

[Jwlehman@aol.com]

In a message dated 2/7/2008 9:06:28 AM Eastern Standard Time, jfruth@tds.net writes:

> The thing that works best for cleaning/polishing the soil probe is a Scotch Brite pad, like the one that comes attached to one side of many cellulose dish-washing sponges.  It is easier to use if you just get the Scotch Brite sans sponge.  The best time to take your readings is right after a soaking rainfall or, like I do, I use distilled water to saturate the soil before I test mine.


Do not use sandpaper. That is a very course abrasive and will scratch off the special metal alloy coating on the shaft, and once that happens your readings will not be accurate. 

Mine did come with operating instructions, then experience via experimenting to use it helped. It also helped to understand how it works. That wasn't part of the instructions. 

How the thing works is the tip is one alloy that reacts with acid to generate a very slight voltage similar to a wet sell battery. The shaft is another alloy that generates a voltage of the opposite polarity. Then depending on the acidity the meter reads the developed voltage and polarity and the meter is calibrated in pH, not microvolts. The metal shaft and tip will not produce a sufficient voltage or none at all if oxide is coating the surfaces. Like wise if the soil is too dry or other problems that block voltage development. But when one gets it right they work great!!! 

Jerry


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