Myron L AG6/PH - Manual (Page 3)

USING YOUR METER
CONDUCTIVITY MEASUREMENT
1. Rinse the celI cup three
times with the sample you want to test.
(For very hot or very cold samples see TEMPERATURE
COMPENSATION below.)
NEVER FILL THE CELL BY DIPPING THE METER INTO WATER!
2. Fill the cell with another sample to at least 1/4" (6mm) above the
upper electrode.
3. Press the black button.
4. Read the conductivity in millimhos indicated by the pointer on
the dial's black scale.
5. (AG-50NLY) If the pointer goes off the scale to the right try RANGE
DOUBLING (see FIELD CALIBRATION).
NOTE: When you are finished with the meter, RINSE THE CELL
CUP with clean water, preferably distilled or deionized.
pH MEASUREMENT (AG6/pH ONLY)
1. Obtain sample to be tested, if necessary, heat or cool it to between
50 ° and 160 ° F (10 ° - 71 ° C).
2. Remove the pH compartment cap and sharply shake out any
liquid.
3. Pour or squirt the sample into the built-in cell cup, especially the
small pH compartment. Shake out and repeat three times with
the sample to be tested. These may be the same rinsings used
to condition the cell forthe conductivity measurement.
4. Press the red button. The pointer immediately indicates the pH
of the sample on the red scale. If the pointer drifts wait
approximately 30 seconds and press the button again to obtain
a stable reading of pH. If drifting continues, the electrode may be
coated with a film. Use a liquid cleanersuch as Windex
™ or
Fantastic ™ to clean the pH sensor bulb.
5. Rinse both pH and conductivity parts of the cell with clean water.
LEAVE SOME LIQUID IN AND RECAP THE pH
COMPARTMENT.
TEMPERATURE COMPENSATION:
For very hot or very cold solutions let the three rinse samples
each remain in the cell for several seconds, then immediately fill the
cell with the sample you want to test. This allows the automatic
temperature compensation feature time to work properly.
CAUTION
ALWAYS rinse the cell cup with pure water immediately after use or
cleaning. This will prevent the build-up of unwanted deposits and
possible contamination of the sample.
DO NOT use with samples hotter than 160
°
F (71
°
C). The readings
WILL NOT be accurate.
DO NOT splash solvents such as lacquer thinner, acetone, benzene
or chlorinated solvents on the plastic case.
DO NOT fix or modify the meter. That will void your warranty. See
SERVICE for details or consult Myron L Company.
DO NOT DIP THE INSTRUMENT INTO WATER. If water does get
inside the instrument, see MAINTENANCE for instructions on drying
it.
ALWAYS store your pH sensor wet and with the cap on (AG6/pH
ONLY).
DO NOT test solutions which could damage the pH sensor. See
MAINTENANCE (AG6/pH ONLY).
DO NOT store meter in direct sunlight.
SOIL TESTING
CONDUCTIVITY AND pH
1. Collect samples which are representative of the area you are
testing. Avoid the upper half inch or so, as salts accumulate there
because of the surface evaporation.
2. If you have the time, dry the sample. Place it on a paper towel or
clean surface and allow it to dry. Rapid drying such as in an oven
is not recommended since some nutrients may be vaporized.
3. When using tap water to dilute soil, test the conductivity of the
water alone. This figure will be subtracted from the conductivity
value of the soil/water mixture solution. It is not necessary to
measure the conductivity of deionized or distilled water as it is
not high enough to affect the mixture's final conductivity reading.
4. If using the Myron L Soil Test Kit, place the dried soil sample in
the smaller vial to either the 2:1 or 5:1 soil line. A 2:1 water-to-
soil ratio is usually sufficient. However, organic media such as
peat moss need a 5:1 water-to-soil test solution.
NOTE: If you are not using the Myron L Soil Test Kit, mix 3 oz. (by
volume not weight) of dried soil and 6 oz. water in a container. Organic
media use a 5:1 water-to-soil ratio.
5. Pour the measured soil sample into the larger vial.
6. Twice fill the smaller vial with water to the upper line and pour it
into the vial containing soil.
IMPORTANT: MUST BE DONE TWICE.
7. Cover the large vial with the cap provided and shake vigorously
to dissolve all soluble salts.
8. Let stand at least 45 minutes to 1 hour. If possible, let stand
overnight to allow complete settling out of suspended particles.
9. Decant off the water into another container or directly into the
Agri-Meter cell cup. Filter paper or cloth may be used for additional
filtration. Paper towels can alter both the conductivity and pH of
the sample, and should not be used as filters.
10. Rinse the cell cup with this sample twice. If using Model AG6/pH
be sure to sharply shake out samples to clear the pH sensor
chamber.
NOTE: If you are also planning to perform the Alkalinity test (see
below), save the rinse samples for that test.
11. Fill the cell cup a third time. Press the black button for conductivity
(salinity) reading on the black scale. If tap water was mixed with
soil, remember to subtract the conductivity reading taken before
mixing. The difference is the soil conductivity. If you need
assistance in determining correct salinity limits or concentrations
contact your fertilizer supplier consultant, or university.
12. For model AG6/pH, press the red button and read pH on the red
scale.
TESTING ALKALINITY
1. Pour a few drops of the sample water and one of the Alkalinity
Test Tablets into the Alkalinity Test Vial.
2. Cap the vial and swirl the sample until the tablet completely
dissolves. The solution should turn a deep violet color.
3. Uncap the vial and gradually add sample water, agitating to keep
the solution well mixed. Continue this until the sample suddenly
turns green.
4. Read the alkalinity in ppm by comparing the solution level to the
scale on the side of the vial.
NOTE: Thoroughly rinse the Alkalinity Test Vial with clean
water after each test.