HM Digital® DM-1: In-Line Dual TDS Monitor

A TDS monitor, like the HM Digital® DM-1 TDS Monitor, is a vital part of any RO/DI system.

It plays a major role in ensuring that your system is performing at it’s best and continues to do so. It will alert you to when it is time to replace RO membranes and DI resin as well as ensure that the production water you are placing into your RO storage container is of the best quality possible with a 0 ppm TDS reading. Without a monitor, it is all just guesswork.


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SKU: HMD-DM1-TDSM Category: Tags: , ,


The DM-1 is consumer friendly monitor measuring feed (input) water vs. product (output) water of a water filtration system at any time. This device is ideal for Reverse Osmosis (RO), Deionised water (DI) filtration systems that work well in a variety of applications such as drinking or potable water, Aquariums, Hydroponics and many more.



  • Displays TDS levels feed water and product water with in & out electrode probes
  • Efficient and accurate with advanced microprocessor technology
  • Auto-Off function conserves battery power. (Shuts off automatically after 10 minutes of non-use)
  • Factory Calibrated: Meters are calibrated with a 342 ppm NaCl solution. Meters can be recalibrated with a mini-screwdriver.
  • Comes equipped with Mur-lok® Quick-Connect T-fittings
  • Installs quickly and easily



Range:0-9990 ppm Dual Range 0-9990 ppm (From 0 – 999 ppm the resolution is 1 ppm. From 1000 to 9990 ppm, the resolution is 10 ppm, indicated by a blinking ‘x10’ image.)
Conversion Factor:NaCl (avg. 0.5)
Cable Length:62cm (including sensor)
Fittings:1/4″ standard push-fit
Power source:2 x 1.5V button cell batteries (LR44 or equivalent; included)
Battery life:approx. 1000 hours of continuous use
Size:7.6 x 2 x 4.7 cm
Weight:79.4 g (2.8 oz.)
UPC: 891144000052




  • Swallowing may lead to serious or fatal injury in as little as 2 hours, due to chemical burns and potential perforation of the esophagus.
  • Never allow children to replace button batteries of any device.
  • If you suspect your child has swallowed or inserted a button battery immediately call the 24-hour Poisons Information Centre on 13 11 26 for fast, expert advice.
  • Regularly examine devices and make sure the battery compartment is correctly secured, e.g. that the screw or other mechanical fastener is tightened. Do not use if the battery compartment is not secure.
  • Dispose of used button batteries immediately and safely out of the reach of children. A battery can still be dangerous even when it can no longer operate the device.
  • Tell others about the risk associated with button batteries and how to keep their children safe.

Additional information

Weight.1 kg
Dimensions15 × 11 × 2.5 cm

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