---
product_id: 2742434
title: "HM Digital DM-1 In-Line Dual TDS Monitor, 0-9990 ppm Range, +/- 2% Readout Accuracy,Blue & White"
brand: "hm digital"
price: "VT9199"
currency: VUV
in_stock: true
reviews_count: 8
category: "Hm Digital"
url: https://www.desertcart.vu/products/2742434-hm-digital-dm-1-in-line-dual-tds-monitor-0
store_origin: VU
region: Vanuatu
---

# +/- 2% readout accuracy 0-9990 ppm TDS range Dual in-line sensor setup HM Digital DM-1 In-Line Dual TDS Monitor, 0-9990 ppm Range, +/- 2% Readout Accuracy,Blue & White

**Brand:** hm digital
**Price:** VT9199
**Availability:** ✅ In Stock

## Summary

> 💧 Know Your Water, Own Your Health — Stay Pure, Stay Ahead!

## Quick Answers

- **What is this?** HM Digital DM-1 In-Line Dual TDS Monitor, 0-9990 ppm Range, +/- 2% Readout Accuracy,Blue & White by hm digital
- **How much does it cost?** VT9199 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.vu](https://www.desertcart.vu/products/2742434-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

- • **Sleek & User-Friendly:** Clear digital display with simple button controls and auto shut-off for energy efficiency and convenience.
- • **Dual Sensor Monitoring:** Simultaneously track tap water and purified water TDS levels for real-time filtration performance insights.
- • **Effortless Installation:** Compact design with quick-connect T-fittings and included batteries means you’re up and running in minutes—no plumber needed.
- • **Precision You Can Trust:** Advanced microprocessor tech delivers ultra-accurate TDS readings within ±2%, ensuring your water quality never goes unchecked.
- • **Stay Ahead of Contaminants:** Instantly detect changes in water purity to protect your health and optimize your filtration system’s lifespan.

## Overview

The HM Digital DM-1 In-Line Dual TDS Monitor offers precise water quality measurement with a wide 0-9990 ppm range and ±2% accuracy. Featuring dual sensors for simultaneous input/output monitoring, it’s designed for easy installation on filtration systems like RO and DI. Compact, battery-powered, and user-friendly, it empowers professionals to maintain optimal water purity effortlessly.

## Description

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.

Review: Good quality product. - Works great. Does exactly what it was intended to do. No leaks.
Review: Excellent TDS Monitor - There is no reason not to give this product the highest rating. The price was right, it does exactly what it is supposed to do and it is easy to install. The meter is simple to install; I have mine mounted with clamps right onto the side of the RO gland. Simply push the button for power and select, back and forth if you wish, the input water TDS or the output water reading. The display is easy to read and it turns off by itself. I personally like to stay in the habit of manually turning off equipment when not needed. I checked it with a professional meter and the readings were identical. It is so convenient to use, allowing frequent checks that will keep the water quality up. Don't be surprised, it is smaller than one would expect, but not a problem, its still easy to read from an arms length.

## Features

- 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

## Technical Specifications

| Specification | Value |
|---------------|-------|
| Brand | HM Digital |
| Material | Plastic |
| Measurement Accuracy | +/- 0.001 inches |
| Number of Batteries | 2 LR44 batteries required. (included) |
| Product Dimensions | 1.9"L x 0.8"W |
| Range | 9990 ppm |

## Product Details

- **Brand:** HM Digital
- **Material:** Plastic
- **Measurement Accuracy:** +/- 0.001 inches
- **Product Dimensions:** 1.9"L x 0.8"W
- **Range:** 9990 ppm

## Images

![HM Digital DM-1 In-Line Dual TDS Monitor, 0-9990 ppm Range, +/- 2% Readout Accuracy,Blue & White - 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 quality product.
*by R***N on November 22, 2025*

Works great. Does exactly what it was intended to do. No leaks.

### ⭐⭐⭐⭐⭐ Excellent TDS Monitor
*by J***R on March 7, 2013*

There is no reason not to give this product the highest rating. The price was right, it does exactly what it is supposed to do and it is easy to install. The meter is simple to install; I have mine mounted with clamps right onto the side of the RO gland. Simply push the button for power and select, back and forth if you wish, the input water TDS or the output water reading. The display is easy to read and it turns off by itself. I personally like to stay in the habit of manually turning off equipment when not needed. I checked it with a professional meter and the readings were identical. It is so convenient to use, allowing frequent checks that will keep the water quality up. Don't be surprised, it is smaller than one would expect, but not a problem, its still easy to read from an arms length.

### ⭐⭐⭐⭐⭐ Easy to install, works like a charm.
*by K***N on August 16, 2024*

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.

## Frequently Bought Together

- HM Digital DM-1 In-Line Dual TDS Monitor, 0-9990 ppm Range, +/- 2% Readout Accuracy,Blue & White
- Aquatic Life 4-Stage Reverse Osmosis Deionization Water Filter System RO/DI Filtration Unit with Carbon Plus Cartridge, 100 GPD
- 1/4 inch Tube Float Valve Kit for RO Water Reverse Osmosis System water filter Push in to Connect Pipe Hose Tube Fittings CCK tube（ball valve +L+15 feet pipe） (blue)

---

## Why Shop on Desertcart?

- 🛒 **Trusted by 1.3+ Million Shoppers** — Serving international shoppers since 2016
- 🌍 **Shop Globally** — Access 737+ million products across 21 categories
- 💰 **No Hidden Fees** — All customs, duties, and taxes included in the price
- 🔄 **15-Day Free Returns** — Hassle-free returns (30 days for PRO members)
- 🔒 **Secure Payments** — Trusted payment options with buyer protection
- ⭐ **TrustPilot Rated 4.5/5** — Based on 8,000+ happy customer reviews

**Shop now:** [https://www.desertcart.vu/products/2742434-hm-digital-dm-1-in-line-dual-tds-monitor-0](https://www.desertcart.vu/products/2742434-hm-digital-dm-1-in-line-dual-tds-monitor-0)

---

*Product available on Desertcart Vanuatu*
*Store origin: VU*
*Last updated: 2026-02-12*