Portable, Handheld, Pen Conductivity Meters / TDS Meters

EC or Electrical Conductivity of water is its ability to conduct an electric current. Salts or other chemicals that dissolve in water can break down into positively and negatively charged ions, these free ions in the water conduct electricity, so the water electrical conductivity depends on the concentration of ions.Salinity and total dissolved solids (TDS) are used to calculate the EC of water, which helps to indicate the water’s purity. The purer water the lower conductivity or TDS. Distilled water is almost an insulator (TDS: few ppm), but saltwater is a very efficient electrical conductor (Seawater TDS around 35,000 ppm).

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TDS-3 HM TDS Meter

HM TDS-3, Handheld TDS Meter with Case (Genuine)

 

Handheld TDS Meter with Case

Measurement range: 0-9990 ppm

Regular price $39.00
Sale price $39.00 Regular price $60.00
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Conductivity Meter EC-3

HM Digital EC-3 Handheld Water Conductivity Meter with Case

 

Measurement range: 0-9990 µS

HM Digital EC3 is Ideal for all water purification applications, wastewater regulation, aquaculture, hydroponics, and colloidal silver. Perfect for both consumer or commercial use. Carry one in your pocket or toolbox at all times.

Regular price $39.00
Sale price $39.00 Regular price $65.00
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Conductivity TDS Meter COM-100
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Conductivity TDS Meter COM-100

HM COM-100, Waterproof Handheld Water Conductivity Meter and TDS Meter

Measurement range: 0-9990 µS;
0-8560 ppm.,
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HM COM 100 portable conductivity meter is Ideal for all water quality testing, water salinity testing, water purification applications, RO Systems, wastewater regulation, aquaculture, hydroponics, colloidal silver, labs & scientific testing, pools & spas, ecology testing, boilers & cooling towers, water treatment and more. The HM COM-100 is a professional level EC/TDS meter at an unbeatable price.

Regular price $98.00
Sale price $98.00 Regular price $150.00
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Handheld Aquarium TDS Meter, TDS-4TMA

TDS-4TMA, Handheld Aquarium TDS Meter with Digital Thermometer

The TDS-4TMA handheld meter is ideal for testing TDS and salt levels of freshwater aquariums and ponds. It can also be used for testing water filtration and purification systems, such as RO and DI, to know when to changes filters and membranes.

HM TDS-4 Salinity Meter Features:

- Measures TDS, water salinity and salt levels of freshwater up to 9990 ppm.
- Includes an internal digital thermometer (celsius only).
- Hold Function - Locks the reading on the screen outside of the water.
- Auto-off function - Turns off meter after 10 minutes of non-use to conserve batteries.
- Dual Range - Measures from 0 - 999 ppm, with a resolution of 1ppm. From 1000 to 9990 ppm, the resolution is 10 ppm, indicated by a blinking 'x10'
image.
- Factory Calibrated: our meters are calibrated with a 342 ppm NaCl solution. Meters can be recalibrated with a mini-screwdriver.
- Recommended for fresh water aquariums, aquaculture and ponds.
- Includes an aquarium-specific packaging.

TDS-4TMA Specifications:

TDS Range:                0 - 9990 ppm (mg/L)
Temp. Range:             0 - 80 degrees Celsius
Resolution:                  0-999: 1 ppm; 1000-9990: 10 ppm (indicated by a 'x10' icon)
Temperature Resolution: 0.1 degree Celsius (Celsius only)
Accuracy:                   +/- 2%
EC-to-TDS Conversion Factor: NaCl (avg. 0.5)
ATC:                            Built-in sensor for Automatic Temperature Compensation of 1 to 50 C (33 to 122 F)
Power source:             2 x 1.5V button cell batteries (included) (LR44 or equivalent)
Battery life:                  1000 hours of usage
Dimensions:                14 x 2.3 x 1.5 cm (5.5 x 0.9 x 0.55 inches)
Weight with case:        34g (1.2 oz).

 

 

Regular price $54.00
Sale price $54.00 Regular price $70.00
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Australia’s supplier of electrical conductivity meter for water testing.
Hand held water conductivity meter / TDS meter pen type to measure salinity of water.

Inline TDS Monitors / Inline Conductivity Monitors

Inline TDS meter HM SM-1
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Inline TDS meter HM SM-1

HM Digital SM-1 Single TDS Meter Monitor 

Measures the tap or any other water source such as water coming out of your purification system for TDS.

Regular price $52.00
Sale price $52.00 Regular price $65.00
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Inline Conductivity Meter HM SM-1EC
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Inline Conductivity Meter HM SM-1EC

HM Digital SM-1EC Inline Conductivity Meter

Real-time monitoring of your water’s electrical conductivity.

Perfect for RO, DI, watermakers, coolers, and any inline filtration system.

Why Choose the SM-1EC Conductivity Monitor?

  • Accurate EC Measurement: Tracks total dissolved solids via conductivity with ±2% precision.
  • Easy System Maintenance: Live EC readings tell you exactly when to service filters or resin.
  • User-Friendly Display: Single-line digital readout with auto-off after 10 minutes to save battery.

What’s Included

  • SM-1EC Inline Monitor: Single-line digital conductivity display.
  • 1/4″ T-Fitting: Quick-connect PVC fitting for simple installation.
  • Batteries: 2 × LR44 button cells pre-installed (approx. 1000 hrs use).

Compatible With:

  • Reverse Osmosis (RO) systems
  • Deionization (DI) water systems
  • Watermakers and coolers
  • Aquarium and hydroponic setups

Specifications

  • Range: 0–9990 µS/cm
  • Resolution: 1 µS (0–999), 10 µS (1000–9990, with “×10” indicator)
  • Accuracy: ±2%
  • Conversion Factor: NaCl (avg. 0.5)
  • Cable Length: 22″ (including probe)
  • Fittings: 1/4″ T-fitting (3/8″ or 1/2″ optional)
  • Power: 2 × LR44 button cells (included)
  • Battery Life: ~1000 hrs continuous
  • Size: 7.6 × 2 × 4.7 cm (3″ × 0.8″ × 1.9″)
  • Weight: 79.4 g (2.8 oz)
  • Origin: Made in Korea by HM Digital

Applications

  • Monitoring RO membrane and DI resin performance
  • Ensuring water quality in watermakers and coolers
  • Managing conductivity in aquariums and hydroponics

Keep your filtration system performing at its best with the HM Digital SM-1EC—your trusted inline conductivity monitor.

Regular price $55.00
Sale price $55.00 Regular price $70.00
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Inline Dual TDS Meter, DM-1 TDS Monitor
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Inline Dual TDS Meter, DM-1 TDS Monitor

HM Digital DM-1 Dual Inline TDS Meter

Measure and monitor your water quality in real time—before and after filtration.

Designed for all water filtration and reverse osmosis systems. Ideal for RO/DI setups, coolers, watermakers, and more.

 

Why Choose the DM-1 TDS Monitor?

  • Real-Time Water Quality Insight: Instantly see the Total Dissolved Solids (TDS) levels of your input and output water.
  • Know When to Change Filters: Monitor performance and get a clear indication when it's time to replace membranes or DI resin.
  • Reliable and Easy to Use: Highly accurate digital readout with automatic shut-off to preserve battery life.

What’s Included

  • Dual Inline TDS Display: Shows both incoming (feed) and outgoing (product) water TDS levels simultaneously.
  • Quick-Connect T-Fittings: Includes two 1/4″ tee fittings for fast, easy installation.
  • Pre-Installed Batteries: Comes ready to use with 2 x 1.5V LR44 button cell batteries included.

Compatible With:

  • Reverse Osmosis (RO) Systems
  • Deionization (DI) Filters
  • Coolers, watermakers, and most inline water filtration systems
  • Can be adapted to 3/8″ or 1/2″ systems (optional fittings required)

Specifications

  • Measurement Range: 0–9990 ppm
  • Accuracy: ±2%
  • Resolution: 1 ppm (0–999), 10 ppm (1000–9990, with x10 indicator)
  • Calibration: Factory calibrated with 342 ppm NaCl solution; adjustable with screwdriver
  • Cable Length: 24.5″ including sensors
  • Battery Life: Approx. 1000 hours continuous use
  • Power Source: 2 x LR44 button cell batteries (included)
  • Dimensions: 7.6 x 2 x 4.7 cm (3 x 0.8 x 1.9 in.)
  • Weight: 79.4 g (2.8 oz.)
  • Origin: Made in Korea by HM Digital
  • Shipping: Free Australia-wide

Installation Tip

To ensure accurate readings and avoid damage during installation:

  • Install the sensor probes straight and securely into the water line.
  • Avoid over-tightening or angling the fittings, which could affect sensor performance or lead to leaks.

Usage Guidelines

  • Use only with clean water lines free of debris or biofouling.
  • Monitor both feed and product water regularly to track system health.
  • Replace filters or membranes as soon as TDS readings indicate performance drop.

Keep your water system performing at its best with the HM Digital DM-1—your eyes on water purity at all times.

Regular price $56.90
Sale price $56.90 Regular price $75.00
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