---
product_id: 254566832
title: "HM Digital DM-1 In-Line Dual TDS Monitor, 0-9990 ppm Range, 2% Readout Accuracy"
brand: "hm digital"
price: "₨16014"
currency: LKR
in_stock: true
reviews_count: 6
category: "Hm Digital"
url: https://www.desertcart.lk/products/254566832-hm-digital-dm-1-in-line-dual-tds-monitor-0
store_origin: LK
region: Sri Lanka
---

# 0-9990 ppm TDS range 1000 hrs battery life 2% readout accuracy HM Digital DM-1 In-Line Dual TDS Monitor, 0-9990 ppm Range, 2% Readout Accuracy

**Brand:** hm digital
**Price:** ₨16014
**Availability:** ✅ In Stock

## Summary

> 💧 Know your water, own your purity.

## Quick Answers

- **What is this?** HM Digital DM-1 In-Line Dual TDS Monitor, 0-9990 ppm Range, 2% Readout Accuracy by hm digital
- **How much does it cost?** ₨16014 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.lk](https://www.desertcart.lk/products/254566832-hm-digital-dm-1-in-line-dual-tds-monitor-0)

## Best For

- hm digital enthusiasts

## Why This Product

- Trusted hm digital brand quality
- Free international shipping included
- Worldwide delivery with tracking
- 15-day hassle-free returns

## Key Features

- • **Smart Power Saving:** Auto-off after 10 minutes conserves battery life, keeping your device ready when you need it
- • **Dual Inline Precision:** Simultaneously monitor feed & purified water TDS for real-time filtration insights
- • **Effortless Installation:** Quick-connect fittings and compact design for seamless setup under sinks or coolers
- • **Comprehensive Kit Included:** Comes with batteries, sensors, and fittings—everything to start monitoring instantly
- • **Advanced Microprocessor Tech:** Ensures ultra-accurate 2% readout for trustworthy water quality data

## Overview

The HM Digital DM-1 is a compact, battery-powered in-line dual TDS monitor with a wide 0-9990 ppm range and 2% accuracy. Designed for easy installation on water filtration systems, it provides simultaneous real-time readings of feed and product water TDS levels, helping you verify filter performance and water purity with advanced microprocessor technology and smart power-saving features.

## 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.

Review: good - good
Review: 洗車用純水器のお手軽数値測定のため導入。すでに純水器2台連結で運用してるのでそれぞれの出口に設置。 そのままでは装着できないのでホームセンターで砲金オネジチーズ、takagiのG1/2メスコネクター、ネジ付き蛇口ニップルを２個ずつ購入。desertcartの一緒に購入されてる商品からクイックコネクターも準備。 別途準備したものの方が金額倍くらいかかりました(汗 苦労したかいもあり無事装着でき測定できてます。他レビューから防水ではないみたいなのでモニターの設置場所は検討中です。

## Features

- 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

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B001EHAZGW |
| ASIN  | B001EHAZGW |
| Batteries | 2 LR44 batteries required. (included) |
| Batteries  | 2 LR44 batteries required. (included) |
| Batteries Included? | Yes |
| Batteries Required? | Yes |
| Battery Cell Type | Alkaline |
| Battery life | 1000 Hours |
| Color | Blue & White |
| Customer Reviews | 4.5 4.5 out of 5 stars (2,623) |
| Customer reviews | 4.5 4.5 out of 5 stars (2,623) |
| Date First Available | 7 August 2012 |
| Date First Available  | 7 August 2012 |
| Display Style | LCD |
| Finish | Brass |
| Included components | Bag |
| Installation Method | Click |
| Is Discontinued By Manufacturer  | No |
| Item Package Quantity | 1 |
| Item Weight | 45.4 g |
| Item model number | 716186 |
| Item model number  | 716186 |
| Manufacturer | HM Digital, Inc. |
| Manufacturer  | HM Digital, Inc. |
| Material | Plastic |
| Measurement Accuracy | 2% |
| Number Of Pieces | 1 |
| Part number | DM-1 |
| Power source type | Battery Powered |
| Product Dimensions | 4.83 x 2.03 x 7.62 cm; 45.36 g |
| Product Dimensions  | 4.83 x 2.03 x 7.62 cm; 45.36 g |
| Size | 0-9990 ppm; 1 ppm resolution (0-999), 10 ppm resolution (1000-9990) |
| Style | In-Line |

## Product Details

- **Brand:** HM Digital
- **Material:** Plastic
- **Measurement accuracy:** 2%
- **Product dimensions:** 48L x 20W millimeters
- **Range:** 0-9990 ppm

## Images

![HM Digital DM-1 In-Line Dual TDS Monitor, 0-9990 ppm Range, 2% Readout Accuracy - Image 1](https://m.media-amazon.com/images/I/61BTf3o7vqL.jpg)

## Questions & Answers

**Q: what kind of batteries does this use?**
A: 303/357 Battery - SR44 - Silver oxide 190 mAhModel 357A

**Q: What are the recommended and maximum flow rates? PSI?**
A: FROM HM DIGITAL: There are no recommended flow rates, but there is a maximum pressure rating, which is 232 PSI (16 bar) at room temperature (25C/77F).

**Q: What fittings are used that come in contact with water? are they nsf certified....usually printed on part if it is.**
A: Yes, they are NSF fittings.

**Q: Can this be dropped into a DWC 5 gallon bucket and left in there so to measure the ppm's anytime i turn it on (since wire is sitting in the water) ?**
A: It should not be fully submerged, only the probe up to the threads should go into liquid.
You could probably seal wire end with a conformant coating or silicone though, do NOT get any on probe end.
Yes it can be used in a deep water or reservoir, it does need to have some type of consistent flow in the probe area... to give a consistent reading !  
...get it naysayers, please think before you post inaccurate advice. 
A basic bubbler agitating solution will work.
Be sure to locate probe out of direct bubble area , the bubbles will skew results.
I've also used these in unagitated tanks , they work...but will only read the general area , obviously. 
This will give a general, consistent, read for on the fly observations of nutrient solution, but you still need to compare with a true reading for accuracy.
TLDR
Dont fully trust this as your standard when used for hydro, DO use as a consistent observation guide,check occasionally against a REAL meter/test, and keep it out of bubbles or it'll get wonky readings.

## Customer Reviews

### ⭐⭐⭐⭐⭐ good
*by S***O on 10 October 2025*

good

### ⭐⭐⭐⭐⭐ Review
*by A***ー on 21 September 2025*

洗車用純水器のお手軽数値測定のため導入。すでに純水器2台連結で運用してるのでそれぞれの出口に設置。 そのままでは装着できないのでホームセンターで砲金オネジチーズ、takagiのG1/2メスコネクター、ネジ付き蛇口ニップルを２個ずつ購入。amazonの一緒に購入されてる商品からクイックコネクターも準備。 別途準備したものの方が金額倍くらいかかりました(汗 苦労したかいもあり無事装着でき測定できてます。他レビューから防水ではないみたいなのでモニターの設置場所は検討中です。

### ⭐⭐⭐⭐⭐ Review
*by R***U on 10 May 2024*

Fácil instalar, confiable, me ayuda a ver como esta mi sistema

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*Product available on Desertcart Sri Lanka*
*Store origin: LK*
*Last updated: 2026-01-22*