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HM Digital DM-1 In-Line Dual TDS Monitor, 0-9990 ppm Range, +/- 2% Readout Accuracy,Blue & White

4.7 (13) Write Review
Free shipping on orders over $29.99

$23.43

$ 9 .99 $9.99

In Stock

About this item

  • plastic
  • Imported
  • The DM-1 helps you to measure the tap water coming in vs the purified water going out of your water filtration system at any time
  • The In-Line Dual TDS Meter displays TDS levels of the feed water and product water with in and out electrode probes
  • This TDS Monitor is highly efficient and accurate due to its advanced microprocessor technology
  • Highly efficient and accurate due to its advanced microprocessor technology
  • Auto-Off function conserves battery power. The unit shuts off automatically after 10 minutes of non-use
  • Installs quickly and easily


Product Description

Product Description: How Pure is Your Water? HM Digital's DM-1 is a dual inline monitor that measures TDS from 0 to 9990 ppm. It includes batteries, two sensors and two 1/4" quick-connect T-fittings. The DM-1 is an easy and convenient method of determining TDS levels for water filtration/purification systems such as reverse osmosis (RO), deionization (DI) and more. It's very useful for coolers or under-the-sink systems. For any type of system that removes TDS, you can install the 'IN' sensor on your tap water (before the system) and the 'OUT' sensor on your product water (after your filtration system) to determine the filter/membrane's effective operating (rejection) rate.

From the Manufacturer

In-Line Dual TDS Monitor.


Kelly Peterson
September 2, 2025
I could hardly believe how easy this instrument was to install. It must have taken me at least two minutes and it was up and running producing accurate results, I checked it with my handheld meter. The display is a little small but that's no big thing. Pun intended.😀 a great buy in my opinion.
R. Stubbs
August 4, 2025
a must have. this tells me my TDS out of the tap and after my DI unit (0 out tyvm!) :) make sure you install correctly. there is only 1 way to install them into the line to read correctly, so follow the directions! a must have for a reef tank ro/di unit!
Gregory baker jr
July 17, 2025
Quick install and upgrade at a great price
mbon
July 8, 2025
This meter functions fairly well. If the two sensors don't have enough water around them in fitting they read low, so they need careful placement in T fittings. The meter output matches handheld conductivity and its inexpensive. My main issue is the low contrast LCD display that requires direct view and more than ambient light. The product concept is great and it's easy to switch from source water to RO.
Kathy Mitchum
June 15, 2025
I have tested behind this product. I use the system for my salt water aquarium so water has to be randomly tested. Never had an issue.
steven holliday
June 1, 2025
Easy to hook up took 5 min tops. Have one probe on waste water and the other after the DI media. Takes the guess work out of when to change DI media!
CLIFF & SANDY
May 25, 2025
I installed our first RO water purification system 18 months ago...extremely delighted..pleased with the pure water...routed 2 ..1/4 inch pure water lines ...1 to our Sam Sung fridge...in door water...& .ice crushed..or whole..the 2ed..a single lever pure water faucet on kit sink rim.Over time I wondered about the performance of the RO process...a small hand held PPM...( parts per a million ) instrament...purity tester...seemed to work nicely ..and simple readings.I noticed this In line PPM water ...TESTOR... two sensors..LCD readout...miniature sized ..at a reasonable price....clicked ..that Amazon TO CART...Prime...Thu..arrived Saturday. Installed easily....also...that saying...BATTERIES INCLUDED....installed..ready to test ones water...in coming...and Out going after the RO PROCESS. THE probes..2..all ready to insert into a T fittings.. included.and both pre wired...aprox 2,5 feet of electrical wires attached...a pair of Velcro pads on case rear..stick on and read the display ..raw water in..slide switch on display..throw switch other direction...LCD..reads purified RO water out.A small but detailed operation fold out sheet..simple details to install..About 1/2 hour..all set to test.A small on..off button..auto turn off also..HAY..,! This little read out..it works great..!For sure..5 stars...a must have to monitor your RO pure water delivery....
Customer
May 23, 2025
2 cuts and 2 minutes to install. Works well just a bit hard to read. Worth every penny of $25.
Roberto Lau
May 6, 2025
Fácil instalar, confiable, me ayuda a ver como esta mi sistema
ユーザー
April 7, 2025
DK-works純水器に取付ける為に購入。値段も手頃で、モニター用のセンサー取付けに別途クイックアダプタは必要でしたが簡単に取付け出来ます。また、IN・OUT切替で両側のモニタリングが出来るのは良いですね。当方はOUT側シングルのみモニタリングで使用しています。別の手持TDSモニターと数値比較しても表示は0️⃣を示しています。コスパ的にも機能的にも確認用として充分使えると思います。尚、防水ではないので本体に直接水が掛からない工夫が必要です。
A7
March 17, 2025
Es sencillo de usar. La cslidad parece buena. No necesita regulación
Kausik Das
January 11, 2025
HM is known for making quality instruments for ro/di systems. I own a ro/di system, so it's a must have for me..
Client d'
December 13, 2024
Bon produit