HM Digital

Deluxe Dual Inline TDS Meter with Backlight DM-2

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Discontinued by Bulk Reef Supply
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The DM-2 Commercial Dual Inline TDS Meter from HM Digital has a stronger water resistant casing than the DM-1. This tool monitors the TDS of your reverse osmosis system in two places and lets you know exactly how the system is performing.

DM-2 features include:

  • Especially designed for commercial/industrial applications.
  • Stronger, water-resistant casing.
  • Each water line can be individually calibrated.
  • Backlit Display
  • Extra large, easy-to-read LCD display.
  • Longer, waterproof, shielded cables.
  • Variable mounting bracket.
  • Uses two standard AA Batteries 


BulkReefSupply.com suggests installing the dual TDS meter post membrane and post DI stage. These two readings will notify you when it's time to change the RO membrane and DI resin. This unit features a digital display and comes with two 1/4" GA Murdock Quick Connect Tee's with double o-rings to ensure a proper seal. As with all HM-Digital products, the DM-2 comes factory calibrated.

The DM-2 is an upgrade to the DM-1 TDS Meter:


TDS Meter Installation Instructions

More Information
UPC 891144000052
TDS Meter Type Dual
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Product Questions

How do you calibrate the TDS meter?
Question by: Luis Figueroa on Jun 17, 2016, 8:58 AM
Hey there!
We do not recommend home calibration in most cases however if needed you can follow the instructions int eh PDF listed below.
Answer by: Connor on Jun 17, 2016, 3:57 PM
I noticed my batteries are getting pretty low on this unit. Do you know what batteries it takes? It would be helpful to know before I take it apart. Thanks!
Question by: Devon on Nov 25, 2014, 11:12 AM
Hey Devon,
The DM-2 TDS meter is powered by 2xAA Batteries.
Answer by: Bulk Reef Supply on Nov 25, 2014, 11:12 AM
How is it powered? Plug? Battery?
Question by: Mike C on Sep 27, 2013, 12:01 PM
Hey Mike,
The DM-2 is battery powered, no separate power wire/plug required.
Answer by: Bulk Reef Supply on Sep 27, 2013, 12:01 PM