Skip to content

Agri-Meter Agricultural Meters – pH, Salinity, Alkalinity Testing Instruments

Plant health can be greatly affected by pH (acidic or basic), salinity (soluble salts), and alkalinity, yet these factors are often ignored by growers.

It is easy to test for these three important parameters using a portable Myron L AGRI-METER with Soil Test Kit.

Agri-Meter,Agricultural,Meters,pH,Salinity,Alkalinity,Testing,Instruments,Myron L Company

AG6/pH Features
  • Checks soil pH & salinity
  • Checks water pH & salinity
  • Checks correct fertilizer concentration
  • Checks boiler water conductivity
  • Automatic temperature compensation means no thermometers or adjustments
  • Only a small amount of soil needed for tests
AG-5 Features
  • For testing conductivity/salinity only
  • Budget priced

Soils – Optimum soil pH is essential for obtaining maximum efficiency from fertilizers and herbicides.   This is especially true for artificial growing media which, without buffering capability, are much more pH sensitive than natural soil.  In addition, the pH of artificial soils can vary greatly when new, and must be adjusted (leached) before use.<
Dissolved salts (salinity) in soil must also be monitored to guarantee healthy plants.  Salt build-up in soil can be due to high TDS (total dissolved solids) in water, excess fertilizer, or poor drainage.  Each plant has its own salinity tolerance level.   If excessive salts accumulate in the soil, roots will take in little or no soil solution, resulting in reduced plant growth and quality.

Using a Myron L Model AG6/pH for checking soil salinity and pH is easy. Simply mix one part soil with two parts pure water in the vials provided with the Soil Test Kit.  Some organic media, such as peat moss, need a 5:1 water to soil dilution ratio.  Only a heaping tablespoon of soil is required.  Agitate container vigorously.  Let settle for 45-60 minutes and decant the water into the instrument cell cup.  Push buttons to read directly in millimhos/conductivity (salinity) and soil pH.

Fertilizer Solutions

Regular testing of conductivity insures that fertilizer solutions will contain the optimum level of salinity for maximum plant health and growth.  If a fertilizer injection system is used, it can be easily checked with an AGRI-METER by taking a sample solution as it comes out of the end of the hose or “spaghetti” irrigation tubes.   Proper adjustment of the fertilizer injector can prevent these common problems: over or under feeding, plant damage and fertilizer waste.


Water pH can vary greatly from month to month because of rainfall effect on the aquifer. Irrigation water, if high in soluble salts, can increase soil salinity causing plant damage. AGRI-METER tests water pH and salinity easily and quickly, and readings are given directly in conductivity/millimhos. The correct pH of water used in pesticide solutions is also important in order to insure maximum effectiveness and prevent pesticide “break-down”.

Alkalinity tests are critical to proper pH adjustments of water and floral preservative solutions. The Soil Test Kit includes a simple and quick ppm alkalinity test.

Boiler Water TDS (Total Dissolved Solids) can also be checked with either model. Because the AGRI-METER is automatically temperature compensated, no thermometers or adjustments are required.

Conductivity Terminology

Both AG-5 and AG6/pH AGRI-METERS are calibrated in millimhos, the term most widely used by growers to express electrical conductivity. Some charts may read in other units called micromhos. However, since one millimho equals 1000 micromhos, conversion is easy. Parts per million (ppm) is also sometimes used. Conductivity/TDS fertilizer concentration tables can be obtained from your supplier, consultant, or university advisor.


Agri-Meter,Agricultural,Meters,pH,Salinity,Alkalinity,Testing,Instruments,Myron L Company
Simple to Operate:
Step 1 Rinse AGRI-METER built-in cell cup and fill with sample
Step 2 Push black button and read conductivity
Step 3 Push red button of Model AG6/pH and read pH



Instrument Specifications
pH Range
2-12 pH (AG6/pH only)
Conductivity Range 0-5 millimhos
Accuracy pH – +/-0.2 pH units
Conductivity – +/-2% of full scale
Repeatability +/-1%
Temperature Compensation Automatic (to 25ºC/77ºF) for Conductivity
samples between 50-160ºF (10-71ºC)
Electrodes (built-in) pH – KCI gel-filled; field replaceable
Conductivity – Never need replatinizing
Calibration Easy finger adjustment of pH Zero,
Gain (slope), and Conductivity
Circuitry Solid-state, sealed against moisture
Power Two 9-volt batteries supplied
Battery Life Approximately one year or 2000 tests
Case Heavy gauge textured ABS
Cell Cup Chip & crack resistant polyethylene
Dimensions 3.4″W x 4.5″D x 4.0″H (85 x 129 x 126 mm)
Weight Less than one pound (0.45 kg)