--- product_id: 51747494 title: "HM Digital COM-100 Waterproof EC/TDS/TEMP Meter" brand: "hm digital" price: "507.52 DT" currency: TND in_stock: true reviews_count: 13 category: "Hm Digital" url: https://www.desertcart.tn/products/51747494-hm-digital-com-100-waterproof-ec-tds-temp-meter store_origin: TN region: Tunisia --- # Measures EC up to 9.99 mS IP67 Waterproof ruggedness Temperature range 0-55°C HM Digital COM-100 Waterproof EC/TDS/TEMP Meter **Brand:** hm digital **Price:** 507.52 DT **Availability:** ✅ In Stock ## Summary > 💧 Stay ahead with the ultimate waterproof EC/TDS meter—precision that flows with your lifestyle. ## Quick Answers - **What is this?** HM Digital COM-100 Waterproof EC/TDS/TEMP Meter by hm digital - **How much does it cost?** 507.52 DT with free shipping - **Is it available?** Yes, in stock and ready to ship - **Where can I buy it?** [www.desertcart.tn](https://www.desertcart.tn/products/51747494-hm-digital-com-100-waterproof-ec-tds-temp-meter) ## 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 - • **Multi-Scale Mastery:** Switch seamlessly between µS, mS, ppm, and ppt scales to suit any professional need. - • **Rapid & Reliable Readings:** Fast 0.5-second response time ensures you never miss a critical measurement. - • **Custom Calibration Control:** Digital calibration with three nonlinear EC-to-TDS conversion factors for tailored accuracy. - • **Precision Meets Durability:** Accurate ±2% readings with robust waterproof design for worry-free use anywhere. - • **Future-Proof Replaceable Sensor:** Detachable platinum electrodes extend lifespan—invest once, measure for a lifetime. ## Overview The HM Digital COM-100 is a professional-grade waterproof EC/TDS/Temperature meter featuring IP67-rated rugged housing, multi-scale measurement (µS, mS, ppm, ppt), and customizable digital calibration with three nonlinear conversion factors. It delivers fast, accurate readings (±2%) with a detachable platinum electrode sensor for long-term use, ideal for hydroponics, water quality testing, and any liquid analysis requiring reliable, on-the-go precision. ## Description SPECIFICATIONS -EC Range: 0 - 9990µs; 0 - 9.99 mS -TDS Range: 0 - 8560 ppm (mg/L); 0 - 8.56 ppt -Temperature Range: 0-55 centigrade -Accuracy: +/- 2% -EC to TDS Conversion Factor: Non-linear conversions for KCl, 442TM or NaCl solutions. -Calibration: Digital calibration -Probe: Detachable platinum electrodes> -Power source: 2 x 1.5V AAA Alkaline batteries. Review: Reliable, good quality, good price - Quick summary first and full review below: Positives: Rugged design Waterproof and dust proof Batteries and lanyard included Different measurement options Calibration option Instructions in clear English Gives quick, reliable readings Replaceable sensor (although not readily/cheaply available in UK) Negatives: Screen not very large and not illuminated Instructions in small print Slightly more complicated than simple TDS meter, due to different measurement unit options (although latter is also a plus) I had previously bought a cheap TDS meter, but decided to get something a bit more reliable, as the electrodes don't last forever, anyway. I use it for plant nutrient solutions, but it would work for any liquid application. It displays as TDS in ppm or ppt (at 2 different conversion rates), mS or micro-siemens. Generally, in hydroponics, what's referred to as EC is measured in mS, or if you multiply that by 10, you get the CF value. In case you don't know (I didn't before): TDS meters measure electrical conductivity (EC) and convert that value to TDS, for which there are different conversion rates. You can look up the conversion rates in tables online. This also provides a temperature reading in C or F and automatically compensates for temperature (which otherwise affects the reading). I've not calibrated it yet, so can't say for sure how accurate it is, but am confident it's more than accurate enough for everyday purposes and readings remain the same for multiple measurements. I looked at the Essentials EC meter (only 1 review, but their ph meter has many good reviews), at a slightly lower price, and providing similar specs, but with this one, you can replace just the sensor, which you can't with the Essentials meter. However, the replacement sensor does not seem to be widely available. After a bit of searching, I found out the part # for the sensor: if you search google for "HM Digital SP-C1", you will get some results. Cheapest I saw was on ebay, sent from US, for about £25 with international tracked delivery. This is more than sturdy enough for everyday use, and has an IP67 rating (dust and waterproof for immersion up to 1 meter, though not hermetically sealed). Instructions are in clear English, easy to understand, but the writing is small. It comes in a box with plastic insert, with a ribbon lanyard that fixes to the top and AAA batteries. Measurements stabilise very quickly. The screen is not huge, and displays multiple values, but is easy enough to read with normal eye sight in good light. There's no backlight, which would have been a nice feature for poor lighting situations. Overall, am pleased with it for the price, and would recommend. Review: Figured it will last a life time - so go for the best from the start - how many TDS meters am I going to buy in my life anyway! - This is an excellent piece of kit that I use for drinking water measurements and hydroponics media making. It might be more expensive than other cheapo ones, but it is nice knowing this is super accurate (especially if you calibrate it to cater to whatever you are using it for). I figured I was probably going to buy just one of these TDS meters in my life, so why not just get the best and keep it for life. I can also just change the electrodes in the future if it needs it but from reading the instructions, I probably won't ever have to unless I start a hydroponic farm! The other thing I like about it is that it is waterproof - it feels strange enough dipping something with an electronic display into a solution so not worrying about whether it will be damaged or not and “how far am I dipping it in?” is a real bonus. If you need to monitor EC or TDS of solutions on a regular basis, then this is highly recommended - make sure you have a source of purified (reverse osmosis or de-ionised) water to wash the tip between uses and before storage to make sure that it does indeed last a life time! ## 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 | | Age range (description) | Adult | | Best Sellers Rank | 39,437 in Garden ( See Top 100 in Garden ) 141 in Pool & Hot Tub Testers | | Brand | HM Digital | | Colour | White/Purple | | Country Of Origin | China | | Customer Reviews | 4.4 out of 5 stars 538 Reviews | | Display Type | Digital | | Global Trade Identification Number | 00891144000007 | | Immersion Depth | 1 Metres | | Included Components | HM Digital HMDCOM100 Waterproof EC/TDS And Amp Temperature Combo Meter | | Included components | HM Digital HMDCOM100 Waterproof EC/TDS And Amp Temperature Combo Meter | | Indoor Outdoor Usage | Outdoor | | Item Length | 8.9 Inches | | Item Weight | 120 Grams | | Manufacturer | HM Digital | | Manufacturer Part Number | COM-100 | | Model Name | HMDCOM100 | | Model Number | COM-100 | | Number of Batteries | 1 A batteries required. | | Outer Material | Plastic | | Outer material | Plastic | | Product Care Instructions | Wipe Clean | | Resolution | 0.1 degree celsius | | Response Time | 0.5 seconds | | Reusability | Rechargeable | | Special Features | 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. | | 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. 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. See more | | Specification Met | UL | | Style Name | Contemporary | | UPC | 095225177507 891144000007 | | Unit Count | 1 count | | Upper Temperature Rating | 80 Degrees Celsius | ## Product Details - **Age range (description):** Adult - **Brand:** HM Digital - **Colour:** 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 count ## Images ![HM Digital COM-100 Waterproof EC/TDS/TEMP Meter - Image 1](https://m.media-amazon.com/images/I/51hfD5nFZmL.jpg) ![HM Digital COM-100 Waterproof EC/TDS/TEMP Meter - Image 2](https://m.media-amazon.com/images/I/61IzVp26pKL.jpg) ![HM Digital COM-100 Waterproof EC/TDS/TEMP Meter - Image 3](https://m.media-amazon.com/images/I/61tCsxZirvL.jpg) ![HM Digital COM-100 Waterproof EC/TDS/TEMP Meter - Image 4](https://m.media-amazon.com/images/I/71wQtNYPw7L.jpg) ![HM Digital COM-100 Waterproof EC/TDS/TEMP Meter - Image 5](https://m.media-amazon.com/images/I/71qEIrsAZOL.jpg) ## Available Options This product comes in different **Size** options. ## Questions & Answers **Q: What batteries does it use?** A: Power source: 3 x 1.5V button cell batteries (included) (model LR44 or equivalent) ## Customer Reviews ### ⭐⭐⭐⭐⭐ Reliable, good quality, good price *by S***H on 13 September 2018* Quick summary first and full review below: Positives: Rugged design Waterproof and dust proof Batteries and lanyard included Different measurement options Calibration option Instructions in clear English Gives quick, reliable readings Replaceable sensor (although not readily/cheaply available in UK) Negatives: Screen not very large and not illuminated Instructions in small print Slightly more complicated than simple TDS meter, due to different measurement unit options (although latter is also a plus) I had previously bought a cheap TDS meter, but decided to get something a bit more reliable, as the electrodes don't last forever, anyway. I use it for plant nutrient solutions, but it would work for any liquid application. It displays as TDS in ppm or ppt (at 2 different conversion rates), mS or micro-siemens. Generally, in hydroponics, what's referred to as EC is measured in mS, or if you multiply that by 10, you get the CF value. In case you don't know (I didn't before): TDS meters measure electrical conductivity (EC) and convert that value to TDS, for which there are different conversion rates. You can look up the conversion rates in tables online. This also provides a temperature reading in C or F and automatically compensates for temperature (which otherwise affects the reading). I've not calibrated it yet, so can't say for sure how accurate it is, but am confident it's more than accurate enough for everyday purposes and readings remain the same for multiple measurements. I looked at the Essentials EC meter (only 1 review, but their ph meter has many good reviews), at a slightly lower price, and providing similar specs, but with this one, you can replace just the sensor, which you can't with the Essentials meter. However, the replacement sensor does not seem to be widely available. After a bit of searching, I found out the part # for the sensor: if you search google for "HM Digital SP-C1", you will get some results. Cheapest I saw was on ebay, sent from US, for about £25 with international tracked delivery. This is more than sturdy enough for everyday use, and has an IP67 rating (dust and waterproof for immersion up to 1 meter, though not hermetically sealed). Instructions are in clear English, easy to understand, but the writing is small. It comes in a box with plastic insert, with a ribbon lanyard that fixes to the top and AAA batteries. Measurements stabilise very quickly. The screen is not huge, and displays multiple values, but is easy enough to read with normal eye sight in good light. There's no backlight, which would have been a nice feature for poor lighting situations. Overall, am pleased with it for the price, and would recommend. ### ⭐⭐⭐⭐⭐ Figured it will last a life time - so go for the best from the start - how many TDS meters am I going to buy in my life anyway! *by A***E on 7 March 2016* This is an excellent piece of kit that I use for drinking water measurements and hydroponics media making. It might be more expensive than other cheapo ones, but it is nice knowing this is super accurate (especially if you calibrate it to cater to whatever you are using it for). I figured I was probably going to buy just one of these TDS meters in my life, so why not just get the best and keep it for life. I can also just change the electrodes in the future if it needs it but from reading the instructions, I probably won't ever have to unless I start a hydroponic farm! The other thing I like about it is that it is waterproof - it feels strange enough dipping something with an electronic display into a solution so not worrying about whether it will be damaged or not and “how far am I dipping it in?” is a real bonus. If you need to monitor EC or TDS of solutions on a regular basis, then this is highly recommended - make sure you have a source of purified (reverse osmosis or de-ionised) water to wash the tip between uses and before storage to make sure that it does indeed last a life time! ### ⭐⭐⭐⭐⭐ Accurate and holds calibration *by N***Y on 18 July 2015* I wasted a lot of money on cheap rubbish units before finding the HM Digital COM-100. This unit seems well made, the buttons are easy to use (although I'm not sure why they are offset to the right) and the screen is large and easy to read. I check the calibration with EC calibration fluid regularly and find the meter to be accurate to plus or minus three percent. This accuracy is fine for mixing up plant nutrients and I've not come across anything more accurate for this price ## 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 --- ## 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.tn/products/51747494-hm-digital-com-100-waterproof-ec-tds-temp-meter](https://www.desertcart.tn/products/51747494-hm-digital-com-100-waterproof-ec-tds-temp-meter) --- *Product available on Desertcart Tunisia* *Store origin: TN* *Last updated: 2026-08-27*