---
product_id: 4233698
title: "HM Digital HMDCOM100 Waterproof EC/TDS And Amp Temperature Combo Meter"
brand: "hm digital"
price: "€ 110.09"
currency: EUR
in_stock: true
reviews_count: 13
category: "Hm Digital"
url: https://www.desertcart.hr/products/4233698-hm-digital-hmdcom100-waterproof-ec-tds-and-amp-temperature-combo
store_origin: HR
region: Croatia
---

# Measures EC, TDS & Temp combo Waterproof IP67 rating Fast 0.5s response time HM Digital HMDCOM100 Waterproof EC/TDS And Amp Temperature Combo Meter

**Brand:** hm digital
**Price:** € 110.09
**Availability:** ✅ In Stock

## Summary

> 💧 Take control of your water quality like a pro — precision, speed, and durability in one sleek meter!

## Quick Answers

- **What is this?** HM Digital HMDCOM100 Waterproof EC/TDS And Amp Temperature Combo Meter by hm digital
- **How much does it cost?** € 110.09 with free shipping
- **Is it available?** Yes, in stock and ready to ship
- **Where can I buy it?** [www.desertcart.hr](https://www.desertcart.hr/products/4233698-hm-digital-hmdcom100-waterproof-ec-tds-and-amp-temperature-combo)

## 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

- • **Compact Powerhouse:** Lightweight, pocket-sized design with large, easy-to-read LCD and auto-off for smart battery management.
- • **Speed Meets Accuracy:** Instant 0.5-second response time keeps your workflow efficient and data fresh.
- • **Precision in Every Drop:** Accurately measures electrical conductivity, total dissolved solids, and temperature for total water quality control.
- • **Customizable Calibration:** Three nonlinear EC-to-TDS conversion factors (KCl, 442TM, NaCl) let you tailor readings to your specific water chemistry needs.
- • **Built to Brave the Elements:** IP67 waterproof housing means reliable performance even in wet, rugged environments.

## Overview

The HM Digital HMDCOM100 is a professional-grade, waterproof EC/TDS/Temperature combo meter designed for precise water quality testing across diverse applications including hydroponics, pools, spas, and labs. Featuring a fast 0.5-second response, multiple calibration options, and a rugged IP67-rated housing, it delivers reliable, customizable readings in a compact, easy-to-use form factor.

## Description

Product description: HM Digital's COM-100 is a waterproof combination EC/TDS/Temperature meter that is ideal for all water quality testing, water purification applications, drinking water, wastewater regulation, aquaculture, hydroponics, colloidal silver, labs & scientific testing, pools & spas, ecology testing, boilers & cooling towers, water treatment and more. The COM-100 is a professional level EC/TDS meter at an unbeatable price.

Review: I love it - FWIW, I'm writing the review from the POV of a spa user. You can use this tester for your pool, salt water aquarium or your hydroponic planter. My supposition is, you're looking at this item because you have needs above and beyond simple test strips. With this TDS meter you'll be able to quickly tell what your total dissolved solids (TDS) are. HM also has a pH meter, the PH-200, which I've been enjoying for a few days now. The unit is waterproof, light weight, a bit smaller than the size of a small "C" cell flashlight or about the size of a large cigar. It's easy to use, easy to maintain, small form factor for storage purposes and once calibrated, I feel it's an accurate piece of test equipment that gives you the feel of having control over your spa tub water chemistry. If you're a bit geeky, enjoy the feel of accurate test data and like the peace of mind knowing you have control over your water chemistry, after using this tester a few times, you'll feel confident that you're finally in control of your spa water readings. Yes, the COM-100 is a bit expensive, but if you have the extra green, for the peace of mind and control over your water chemistry this tester gives you, you'll quickly come to the same conclusion I came to; money well spent. Note 1. Be sure to buy some calibration solution so you know your reading is accurate. Calibration is simple. Holding the middle button in for a few seconds puts the unit in calibration mode and then it's simply using the up/down arrows to set the digital display to match the calibration fluids stated concentration level. In this case the calibration fluid concentration is 342ppm. You want to use a calibration fluid that's close to your expected needs. In the case of this tester, calibration is no more difficult than using a television remote control. Note 2. desertcart has "HM Digital Calibration Fluid for Handheld TDS Meter" for sale. You can get calibration fluid in concentrations of either 1000 ppm or 342 ppm. You can get in KCl or NaCl depending on what your water chemistry is. Note 3. FWIW, you want your spa water to be between 1000 - 2000 ppm TDS. When it gets above 3000 ppm, it's time to trash the spa tub water because at 3000 ppm, your chemicals become less effective. Knowing TDS is an important aspect of monitoring your spa water chemistry. Without a TDS tester of this kind, you haven't a clue what your TDS is. Due to this, you're either having to trash your water prematurely on a monthly, two or three month cycle. Or the alternative is, use up a lot of time regularly dropping in at your pool/spa supply house with water sample in hand like the doctors office where they're going want you to spend more money. I hate trashing spa water and I hate spending money on chemicals, just so I feel good about getting my water tested for free. With this tester, that's no longer an issue. Hope the above helps.
Review: Great for testing water quality and hydroponic solutions - Works as stated. Its nice to have different conversion scales (NaCl, KCl, 442). For testing total disolved solid (TDS) aka Part Per Million (PPM), this meter is very accurate within + or -2 . For testing water quality and hydroponic solution strength, most companies recomend the NaCl scale. Fast delivery, clear instruction manual, completely water proof, and interchangeable electrodes...quality product.

## Features

- Measures electrical conductivity (EC), total dissolved solids (TDS), and temperature
- Four scales: µS, mS, ppm, ppt (mS and ppt are new)
- Three different nonlinear ECtoTDS conversion factors (KCl, 442TM, NaCl).
- Waterproof housing (IP67 rating)
- Measurement Range: 09990 µS; 08560 ppm; 09.99 mS; 08.56 ppt

## Technical Specifications

| Specification | Value |
|---------------|-------|
| ASIN | B0045LQFTK |
| Age Range (Description) | Adult |
| Batteries | 2 AAA batteries required. |
| Best Sellers Rank | #65,581 in Industrial & Scientific ( See Top 100 in Industrial & Scientific ) #12 in Conductivity Meters & Accessories |
| Brand | HM Digital |
| Color | White/Purple |
| Date First Available | December 7, 2005 |
| Display Type | Digital |
| Global Trade Identification Number | 00891144000007 |
| Immersion Depth | 1 Meters |
| Included Components | HM Digital HMDCOM100 Waterproof EC/TDS And Amp Temperature Combo Meter |
| Indoor/Outdoor Usage | Outdoor |
| Is Discontinued By Manufacturer | No |
| Item Length | 8.9 Inches |
| Item Weight | 4.2 ounces |
| Item model number | COM-100 |
| Manufacturer | HM Digital |
| Model Name | COM-100 |
| National Stock Number | 4910-01-620-0848 |
| Number of Batteries | 2 AAA batteries required. |
| Outer Material | Plastic |
| Power Source | Battery Powered |
| Product Care Instructions | Wipe Clean |
| Response Time | 0.5 seconds |
| Reusability | Reusable |
| Special Feature | Auto-off function, data-hold function and low-battery indicator., Display: large and easy-to-read LCD screen includes simultaneous temperature reading., Factory Calibrated: The COM-100 meter is calibrated with a 1413 µS solution. The meter can be recalibrated with digital calibration using the push buttons, rather than a screwdriver. |
| Specification Met | UL |
| Style | Practical |
| UPC | 095225177507 891144000007 |
| Unit Count | 1.0 Count |
| Upper Temperature Rating | 130 Degrees Fahrenheit |

## Product Details

- **Age Range (Description):** Adult
- **Brand:** HM Digital
- **Color:** White/Purple
- **Display Type:** Digital
- **Included Components:** HM Digital HMDCOM100 Waterproof EC/TDS And Amp Temperature Combo Meter
- **Outer Material:** Plastic
- **Product Care Instructions:** Wipe Clean
- **Specification Met:** UL
- **Unit Count:** 1.0 Count

## Images

![HM Digital HMDCOM100 Waterproof EC/TDS And Amp Temperature Combo Meter - Image 1](https://m.media-amazon.com/images/I/51hfD5nFZmL.jpg)

## Questions & Answers

**Q: Can this unit be used to test PH?**
A: FROM HM DIGITAL: The COM-100 is NOT a pH meter. It measures EC (electrical conductivity), TDS (total dissolved solids) and temperature. For pH, please purchase HM Digital's PH-200. For more information, please visit www.tdsmeter.com

**Q: My meter want read over 999 or am I looking at the wrong ppm?**
A: Select 442 scale. Your meter will read more than 999 ppm.

**Q: Any trouble measuring in mS?**
A: FROM HM-DIGITAL: The COM-100 is a professional waterproof EC/TDS meter that has three EC-TDS conversion factors and selectable modes allowing you to measure in the µs, mS, ppm and ppt scales. For more information, please visit, www.tdsmeter.com/products/com100.html

**Q: Isn't one supposed to use calibrating and cleaning solution with this?**
A: I clean mine with a wet Q-tip. There is a TDS calibration solution I use when I recalibrate every month.

## Customer Reviews

### ⭐⭐⭐⭐⭐ I love it
*by B***8 on September 3, 2011*

FWIW, I'm writing the review from the POV of a spa user. You can use this tester for your pool, salt water aquarium or your hydroponic planter. My supposition is, you're looking at this item because you have needs above and beyond simple test strips. With this TDS meter you'll be able to quickly tell what your total dissolved solids (TDS) are. HM also has a pH meter, the PH-200, which I've been enjoying for a few days now. The unit is waterproof, light weight, a bit smaller than the size of a small "C" cell flashlight or about the size of a large cigar. It's easy to use, easy to maintain, small form factor for storage purposes and once calibrated, I feel it's an accurate piece of test equipment that gives you the feel of having control over your spa tub water chemistry. If you're a bit geeky, enjoy the feel of accurate test data and like the peace of mind knowing you have control over your water chemistry, after using this tester a few times, you'll feel confident that you're finally in control of your spa water readings. Yes, the COM-100 is a bit expensive, but if you have the extra green, for the peace of mind and control over your water chemistry this tester gives you, you'll quickly come to the same conclusion I came to; money well spent. Note 1. Be sure to buy some calibration solution so you know your reading is accurate. Calibration is simple. Holding the middle button in for a few seconds puts the unit in calibration mode and then it's simply using the up/down arrows to set the digital display to match the calibration fluids stated concentration level. In this case the calibration fluid concentration is 342ppm. You want to use a calibration fluid that's close to your expected needs. In the case of this tester, calibration is no more difficult than using a television remote control. Note 2. Amazon has "HM Digital Calibration Fluid for Handheld TDS Meter" for sale. You can get calibration fluid in concentrations of either 1000 ppm or 342 ppm. You can get in KCl or NaCl depending on what your water chemistry is. Note 3. FWIW, you want your spa water to be between 1000 - 2000 ppm TDS. When it gets above 3000 ppm, it's time to trash the spa tub water because at 3000 ppm, your chemicals become less effective. Knowing TDS is an important aspect of monitoring your spa water chemistry. Without a TDS tester of this kind, you haven't a clue what your TDS is. Due to this, you're either having to trash your water prematurely on a monthly, two or three month cycle. Or the alternative is, use up a lot of time regularly dropping in at your pool/spa supply house with water sample in hand like the doctors office where they're going want you to spend more money. I hate trashing spa water and I hate spending money on chemicals, just so I feel good about getting my water tested for free. With this tester, that's no longer an issue. Hope the above helps.

### ⭐⭐⭐⭐⭐ Great for testing water quality and hydroponic solutions
*by A***R on January 4, 2014*

Works as stated. Its nice to have different conversion scales (NaCl, KCl, 442). For testing total disolved solid (TDS) aka Part Per Million (PPM), this meter is very accurate within + or -2 . For testing water quality and hydroponic solution strength, most companies recomend the NaCl scale. Fast delivery, clear instruction manual, completely water proof, and interchangeable electrodes...quality product.

### ⭐⭐⭐⭐ It’s good
*by A***S on November 23, 2025*

Good product. Complicated a bit and needs better instructions

## Frequently Bought Together

- HM Digital HMDCOM100 Waterproof EC/TDS And Amp Temperature Combo Meter
- HM Digital C342 TDS and EC Calibration Solution, 342 ppm (NaCl), 90 ml Volume, Transparent/Blue
- HM Digital 1000ppm TDS Calibration Solution

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*Product available on Desertcart Croatia*
*Store origin: HR*
*Last updated: 2026-03-14*