Loading... Please wait...

COM-100 TDS/EC Meter

Calculated at checkout

Product Description

Ideal for all water quality testing, water purification applications, wastewater regulation, aquaculture, hydroponics, colloidal silver, labs & scientific testing, pools & spas, ecology testing, boilers & cooling towers, water treatment and more.  The COM-100 is a professional level EC/TDS meter at an unbeatable price.  The continuous improvement process at HM Digital yielded certain product design changes beginning in late 2015.  Buckeye Hydro carries only COM-100 meters of the most current design.  


  • Measures electrical conductivity (EC), total dissolved solids (TDS), and temperature.
  • Four scales: EC measurements available in µS (microsiemens) or mS (millisiemens).  TDS measurments available in ppm (parts per million = mg/L) or ppt (parts per thousand).
  • Two non-linear, user-selectable EC-to-TDS conversion factors (442TM, NaCl).
  • Automatic Temperature Compensation (ATC) 
  • Waterproof housing (IP-67 rating)
  • TDS Measurement Range: 0-8560 ppm (442 scale); 0-5000 ppm (NaCl scale)
  • Digital Calibration (push button) to any point within the meter's range
  • Auto-off function, data-hold function and low-battery indicator
  • Display: large and easy-to-read LCD screen includes simultaneous temperature reading.
  • Replaceable Sensor (model SP-C1)
  • Factory Calibrated: The COM-100 meter is calibrated with a 1413 µS solution. The meter can be recalibrated with digital calibration using the push buttons, rather than a screwdriver.
  • Includes a cap, batteries and lanyard.


EC Range: 0 - 9990 µS; 0 - 9.99 mS
TDS Range: 0 - 8560 ppm (mg/L); 0 - 8.56 ppt
Temperature Range: 0-55 °C; 32-130 °F
EC Resolution: 0-99: 0.1 µS; 100-999: 1 µS; 1000-9990: 10 µS
TDS Resolution:  0-99: 0.1 ppm; 100-999: 1 ppm; 1000-9999: 10 ppm
Temperature Resolution:
0.1 °C/F 
Accuracy: +/- 2%
EC to TDS Conversion Factor: Non-linear conversions for 442TM or NaCl solutions, selected by the user. 
Calibration: Digital calibration by push button.
Probe: Detachable platinum electrodes
Housing: IP-67 Waterproof (submersible).  The COM-100 floats.
Power source: Two 1.5V AAA batteries (included).
Dimensions: 7.3 x 1.3 x 1.3 inches
Weight: 4.5 oz


Conductivity: 1 mho = 1 Siemen
Normal unit of measurement is:
1 micromho (µmho) = 1 microSiemen (µS),
1 millimho (mmho) = 1 milliSiemens (mS) = 1,000 µS

Write a review

Product Reviews

This product hasn't received any reviews yet. Be the first to review this product!

Welcome to Buckeye Hydro!
Pure Water Technologies

Our Newsletter

Sign up for exclusive updates and special offers!


Buckeye typcially ships the same day, or less commonly, the day after an order is placed. The majority of our shipments are sent UPS Ground or FedEx Ground. Estimated delivery times for these services are similar, and are shown below. See our policies page for additional shipping information.

Read More About Shipping


When should I replace my filters?
Will Buckeye filters fit properly in my water filtration system?
Do I need to do anything special when I install new cartridges in my RO or RO/DI system?

Read More FAQ