

💧 Measure purity like a pro—because your water quality deserves precision.
The HM Digital TDS-3 is a handheld Total Dissolved Solids meter offering a wide 0-9990 ppm measurement range with 1 ppm resolution and ±2% accuracy. Designed for commercial and professional use, it features a large LCD screen displaying both TDS and temperature, a hold function for saving readings, and comes with a durable carrying case with belt clip. Powered by included LR44 batteries, it delivers reliable, instant water quality testing for applications from filtration systems to hydroponics.
| ASIN | B000VTQM70 |
| Age Range (Description) | Adult |
| Batteries | 2 LR44 batteries required. (included) |
| Batteries Included? | Yes |
| Batteries Required? | Yes |
| Battery Cell Type | Alkaline |
| Battery Life | 3 Hours |
| Best Sellers Rank | #3,941 in Industrial & Scientific ( See Top 100 in Industrial & Scientific ) #2 in Conductivity Meters & Accessories |
| Brand | HM Digital |
| Color | Style 1 |
| Customer Reviews | 4.6 4.6 out of 5 stars (1,728) |
| Date First Available | March 2, 2007 |
| Display Type | LCD |
| Global Trade Identification Number | 00826333000001 |
| Included Components | Carrying case |
| Indoor/Outdoor Usage | Indoor |
| Is Discontinued By Manufacturer | No |
| Item Length | 1 Inches |
| Item Package Quantity | 1 |
| Item Weight | 0.007 ounces |
| Item model number | TDS-3 |
| Manufacturer | HM Digital |
| Measurement Accuracy | 1 |
| Model Name | TDS-3 |
| Number Of Pieces | 10 |
| Number of Batteries | 2 LR44 batteries required. (included) |
| Outer Material | Metal |
| Part Number | TDS-3 |
| Pattern | meter |
| Power Source | Battery Powered |
| Product Care Instructions | Wipe Clean |
| Reusability | Single Use |
| Size | 0 - 9990 ppm. TDS Range, 1 ppm Resolution, +/- 3% Readout Accuracy |
| Special Feature | High Accuracy |
| Special Features | High Accuracy |
| Style | Contemporary |
| Temperature Range | 0/80 Degrees Celsius |
| UPC | 891144000083 826333000001 |
| Unit Count | 1.0 Count |
| Upper Temperature Rating | 50 Degrees Celsius |
J**Y
Perfect tester
I bought the iSpring tester first because it's a known brand. However it was defective when opened the box. Ordered this one instead, it's working as a charm and build quality also exceeded the iSpring by a mile. I recommend this product to anyone who's looking for a water tester affordable and accurate.
D**S
Good, simple, efficient!
Surprisingly helpful and easy to use! We just care about PPM (aka TDS) related to the Reverse Osmosis (RO) filter system we just installed, and this little guy does the trick. Inexpensive and working great for us for 2 weeks now!
M**E
Great TDS Meter for Hydroponics – Easy to Use & Accurate!
I’ve been using the HM Digital TDS-3 for my hydroponic system, and it’s been a game-changer. If you’re serious about growing healthy plants, keeping track of your nutrient levels is crucial, and this little device makes it incredibly easy. What I Like: ✅ Accurate & Reliable – The readings are consistent, and the 0–9990 ppm range covers all my needs. I can easily check if my nutrient solution is too strong or too weak. ✅ Temperature Compensation (ATC) – I don’t have to worry about temperature affecting the accuracy. The meter adjusts automatically. ✅ Super Easy to Use – Just dip it in, wait a couple of seconds, and get an instant reading. The hold function is great for locking the number so I can check after pulling my hand out of my reservoir. ✅ Compact & Battery-Saving – It’s small, comes with a protective case, and has an auto shut-off to save battery life. A Couple of Things to Keep in Mind: ❌ Not Waterproof – Be careful not to drop it in water. I make sure only the probes are submerged. ❌ Doesn’t Measure pH – This is strictly for TDS and temperature, so you’ll need a separate pH meter. Final Thoughts: For the price, this TDS meter is absolutely worth it. It gives me quick, accurate readings and helps me dial in the perfect nutrient levels for my plants. If you’re into hydroponics, aquaponics, or even just checking your water quality, I highly recommend it!
A**N
works great
great product, works great, easy to use. very happy. I would buy this product again.
K**K
Tester works great
Works like it should. Great tester
D**N
Accurately calibrated
What makes this tester stand out against many others: it has adjustable calibration and is calibrated at the factory. I have checked the readings against the reference solution and the calibration is accurate. The build quality is solid as well.
K**Z
It works, seems to be accurate, and is low cost
I tested this with my tap water and filtered water from the fridge. It comes calibrated from the factory, but not sure how long the calibration will last. The measurements were easy to read and matched the report from our water company when testing tap water, and it correctly reported that the hardness value was lower when testing filtered water, so it seems this device works well. I'm happy with it and glad I got it, especially for the low price.
J**N
Cheap but worksahic
This thing is so cool! It's so cheap compared to the alternatives and it is accurate upon arrival. I use it like a lab master and despite all the rough use it's still working.
T**K
After a month’s use monitoring drinking water, I've found it accurate and consistent. The unit delivered came with batteries and a carrying case included. Also included was a note from the suppliers asking me to get in touch if I noticed any errors - nice touch. Some reviewers have noted continuing varying read outs. I've noticed something similar when used with hot water but didn't find this a problem as it was mostly used with room temp water. In my opinion, it's accurate to within plus/minus 2%. This is based on ongoing readings given on municipal water, distilled water and stored samples. Granted, these aren't 'standard' samples but over time these samples confirmed the unit's accuracy and repeatability, in my opinion. I bought it to use as a quick check on my Brita water filter's performance and this it did admirably.
C**L
Usei um medidor e constatei que a água do filtro tem a mesma qualidade da água da torneira, com o mesmo número de resíduos. Tudo foi instalado conforme o manual. O produto me ajudou a ver que fui enganada
A**A
Purtroppo non ci sono istruzioni in italiano
J**E
C'était pareil fonctionne très bien il fait son boulot j'ai déjà changé les piles même avec une utilisation minimes. On verra bien avec les nouvelles piles
A**R
Al parecer mide muy bien el TDS (Total de sólidos disueltos) en el agua. Sin embargo me confundí a comprarlo ya que en realidad quería medir la dureza del agua (cuando busqué "dureza agua" en Amazon salieron infinidad de aparatos para medir el TDS). La dureza es otra cosa (cantidad de magnesio y calcio) mientras el TDS son todos los sólidos. Los suavizadores no afectan el TDS, solo la dureza, y compré el aparato para verificar el funcionamiento de mi suavizador.
Trustpilot
2 weeks ago
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