Triple Inline TDS Meter TRM-1 - HM Digital

Triple Inline TDS Meter TRM-1 with Push Connect Fittings - HM Digital
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  • Triple Inline TDS Meter TRM-1 with Push Connect Fittings - HM Digital
  • Triple Inline TDS Meter TRM-1 - HM Digital

Triple Inline TDS Meter TRM-1 - HM Digital

100% Recommend this to a friend (6 of 6)

SKU: 200219
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Quick Overview

The TRM-1 Triple Inline TDS Meter from HM Digital is one of the most essential reverse osmosis accessories. This tool uses electrode probes to monitor the TDS of your reverse osmosis system in three places and lets you know exactly how the system is performing. suggests installing the triple TDS meter post source water, post membrane and post DI stage. These three 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 three 1/4" Quick Connect Tee's. As with all HM-Digital products, the TRM-1 comes factory calibrated.


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Full Details

TRM-1 TDS Meter Features

  • Advanced microprocessor technology
  • Auto-off function shuts off after 10 minutes of non-use
  • 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.)
  • Factory Calibrated: calibrated with a 342 ppm NaCl solution.


  • Range: 0-9990 ppm
  • Accuracy: ±2%
  • Conversion Factor: NaCl (avg. 0.5)
  • Cable Length: 24.5" (including sensor)
  • Power source: 2 x 1.5V button cell batteries (LR44 or equivalent; included)
  • Size: 7.6 x 2 x 4.7 cm (3 x .8 x 1.9 in.)
  • Weight: 79.4 g (2.8 oz.)


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6 Items

  • Nice product By Tony on 8/3/2015

    Easy to install and nice to see the incoming TDS, post RO and post DI.
  • No more guessing By Mike on 5/14/2015

    Is this RO and DI thing working? I never knew. Now I do. A must have and a breeze to install.
  • Inline tds meter By Nate on 1/22/2015

    Just installed mine along with a new ro membrane. So far this is great I can check whats coming in, after the ro membrane and after the resin.. I have wanted to do this for a year now, so glad that I made the purchase. easy to install just follow directions and you will be fine. LOVE IT!!
  • Perfect for saving money By Paul on 10/22/2014

    I use this TDS meter on my inlet, after my RO membrane, and after my DI cartridges. It works perfect for multiple reasons. First, I know what my TDS coming in and going out of my RO membrane so I can tell if I'm getting the rejection I should and know when it's time to replace my membrane. Next, when I first turn the unit on, I can flush the good water coming out of the membrane until the TDS comes down so I'm not using up resin. This is from TDS creep, read about it if you haven't heard of it. Lastly, it tells me when I need to change my resin as the last one will show me if TDS comes above 0, so I'll know the resin is exhausted. Perfect and not a big investment.
  • Could not be simpler to use By Oz on 9/28/2014

    Product does what it claim and so far seems to do it well. It's very simple to operate.
  • It is great being able to monitor 3 stages of filtration By mfief on 6/26/2014

    Being able to monitor the TDS after the carbon blocks, ro unit, and after the DI resin is great. No need for un necessary filter changes. You can check three phases of filtration in seconds and replace only the necessary filters. This will save money in the long run.

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