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Glossary of Terms

These are common terms used in Myron L® Data Sheets, Application Bulletins and Operation Manuals
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Refers to how close the indication is to the absolutely correct value.  A 1% accuracy on a 0-500 ppm instrument is accurate to within 5 ppm or 1% of 500 = 5.

Bleed Value

A small valve to bleed off small amounts of water from a container vessel or bath.


Removal of liquids or solids from a process/storage vessel or a line by the use of pressure.


Check or adjust the graduations of a quantitative measuring instrument.


Steam which rises and cools to a liquid.  When measuring condensate, liquid Must Be COOLED before pouring it into cell cup of instrument.


The ratio of the electric current density to the electric field in a material. Some materials such as metals, copper, silver, gold, platinum have very high conductivities but other materials such as plastic may have a very low conductivity.  Seawater contains a large quantity of dissolved salts therefore, has a high conductivity.  Deionized water (DI) has a low conductivity.

Conversion Chart

Must be used to convert a parts per million reading to micromho or vice versa because the ppm scales are non linear and the micromho scales are linear. Because of the curve, there is no set ratio so one must refer to the chart.


Removal of mineral constituents from water.


Removal of ionized minerals and salts from a solution by a two phase ion exchange procedure.

DI Water

Deionized water.

Dialysate Meter

Verifies the total concentration of ionized salts in dialysate solutions used in hemodialysis or kidney equipment.


Liquid that has passed through a processing operation.

Electrical Relay

Employs a solenoid to provide mechanical action to move a varying number of electrical contacts back and forth or on and off.


Hydrochloric acid - used to clean scale, accumulations of salts or alkaline condition.


Potassium Chloride - salt used to prepare micromho/microsiemen standards.  If a cell has a range of 0-1000 KCl, it is the same as 0-1000 micromhos.

Linear Meter

The deflection of the pointer is proportional to the quantity measured. Micromho scales are linear.


1,000,000 ohms of resistivity.


A unit of conductance.  The conductance of a conductor in mhos is the reciprocal of its resistance in ohms.  In reference to solutions it is the ability of a solution to conduct current from point A to point B.  Also can be measured in millimhos and micromhos.


Equivalence of 10-6 or one millionth (1/1,000,000). Symbol - µ.


Equivalence of 10-3 or one thousandth (1/1,000). Symbol - m.


Sodium Chloride, salt used to prepare dialysate solutions and some standards.


Sodium Hydroxide - strong base, highly alkaline and highly corrosive.


Pertaining to a response which is not directly or inversely proportional to a given variable.  Parts per million scales are nonlinear.


A unit of resistance to electrical current and ohm is the reciprocal of mho/siemen.  Symbol - Ω .

Parts Per Million / PPM

Concentration expressed as parts of a dissolved solid (salt, in our case) per million parts of pure water.  For example, 1000 ppm of NaCl means 1000 parts NaCl in 1,000,000 parts of pure water.  In very dilute aqueous solutions, ppm is approximately equal to 1 mg solute per 1 liter of solution.  Abbreviated ppm.

Parts Per Thousand / PPT

Concentration expressed as parts of a dissolved solid (salt, in our case) per thousand parts of pure water.  For example, 100 ppm of NaCl means 100 parts NaCl in 1,000 parts of pure water.  Abbreviated ppt.


A term used to describe the hydrogen-ion activity of a system; a solution of pH 0 to 7 is acid, pH of 7 is neutral, pH 7 to 14 is alkaline.  Our pDS Meters have scales of 2 - 12 pH and our digital instruments have scales of 0 - 14 pH.

Product Water

Water that has completed a recycling process.

Potable Water

Suitable for drinking (US standard 500 ppm).

Potassium Chloride

Salt used to prepare micromho/microsiemens standards (KCl).


Same reading each time for the same solution.

Resin Bed

Tank filled with resins and water is forced through these resins and the resins latch onto the conductive ions or dissolved solids in the water.


The opposition of a medium which opposes or reduces current flow.  Any substance which reduces or eliminates current flow, reciprocal of conductivity.

Reverse Osmosis

A method of water treatment by forcing pure water to pass through membranes that will not pass sodium or chloride ions.


A buildup of mineral, salts on surfaces of boilers, cooling towers, swimming pools (any interior surface of water liners or containers).  Scale can build up in cell cup of instrument.  This will insulate the electrodes from the solution to be measured, so it must be free from scale.

Scales (Dials)

A means of measuring by graduated marks.  Myron L® instruments use both linear and non-linear scales depending on the model instrument. Measurement can be read in ppm or mhos e.g. DS Meter may have a scale with 50 divisions for each ppm.  0-500 ppm scale has divisions for each 10 ppm. 0-5000 ppm scale has a division for each 100 ppm.


Amount of salt in a solution.


See MHO.  Also can be measured in millisiemens (mS) and microsiemens (µS).  Symbol - S

Sodium Chloride

See NaCl (table salt) used to prepare some standards.

Solenoid Value

A valve actuated by a solenoid for controlling the flow of gases or liquid in pipes.

Temperature Compensation

A solution which has a certain conductivity at a specific temperature will, when heated, increase its conductivity.  When that same solution is cooled or chilled, it will decrease its conductivity.  Temperature compensation means the conductivity reading will automatically adjust to what that solution would have read at a standard temperature.  Our instruments are compensated to 25°C or 77°F.

Total Dissolved Solids / TDS

The total solids dissolved in a solution.  This is a measurement of all conductive ions in the solution.  Abbreviated TDS.


The ability of an electronic circuit to indicate known values across its entire operating range when, a predetermined coinciding current is applied to it.

442™ Solutions

This is the Myron L® Company standard of natural water. 40% sodium sulfate, 40% sodium bicarbonate, 20% sodium chloride.

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