Refer to TDS/Conductivity Equivalents chart for actual calibration point values.
RE-10 Range Extenders are usually calibrated with either 442-15,000 or 442-
30,000 Standard Solution.
Conductivity instruments are a convenient way to determine the parts per million
of total dissolved solids (ppm/TDS) in boilers, cooling towers, reverse osmosis
systems, etc. Although the International Unit (Sl) of measuring conductivity is
the microsiemens/ cm (also known as micromhos/cm), a direct reading in ppm/TDS
is sometimes preferred.
conductivity instruments and monitor/ controllers are calibrated to read in ppm/442,
ppm/ NaCI, or microsiemens. All three values are listed on our Standard
Solutions. The relationship among these standards can be seen in the table and
graphs that follow.
442 Natural Water™ Standard Solution
is used in calibrating many Myron L® Instruments. It is the best choice when
measuring boiler and cooling water samples, city water supply, lakes, wells,
etc. "442" refers to the combination of salts mixed with deionized water to
comprise this standard: 40% sodium sulfate, 40% sodium bicarbonate, 20% sodium
chloride. A combination of standard salts is necessary since natural water salt
type and concentration can vary greatly by location. After much research, the
442 Standard was developed by the Myron L® Company more than 40 years ago. It
remains the world's most accepted standard.
NaCl Standard Solution is offered to
calibrate instruments that measure any sample that is predominately NaCI (sodium
chloride), such as sea water, brackish water, etc. As can be seen in the graph
at right, 1000 ppm of NaCI has a conductivity of 2000 micromhos. Note how this
1:2 relationship is continuously variable throughout the curve and decreases as
ppm NaCI increases.
KCl Standard Solution is used to
calibrate conductivity instruments that read directly in microsiemens (micromhos)
or millisiemens (1000 microsiemens). KCI (potassium chloride) is a very stable
salt and is an international calibration standard for conductivity measurement.
pH Buffer Solutions 4, 7 and 10 are
mold inhibited and accurate to within + 0.01 pH units @ 25°C. Myron L® Buffers
are traceable to NIST certified pH references and are color-coded for instant