HM Digital TDS-3 Handheld TDS Meter With Carrying Case, 0 - 9990 ppm TDS Measurement Range, 1 ppm Resolution, +/- 2% Readout Accuracy

Cost was under $20. Used it to determine that the RO membrane I was about to replace was still working above acceptable rejection rate level. Saved $90.

Very nice TDS meter. Easy to use and I believe it is accurate. I will do a calibration later. But, there is always an "it would be nice". That being said, it would be nice if it had a backlit screen. Otherwise, perfect.

The media could not be loaded. 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!

This device provides an instant value for TDS. It’s very easy to use and read.

Thank god for amazon as they allow return of items thatdo not work well. I have tried ten of these TDS pens and this one that looks like this has three manufacturers but they have this shape and they all have the adjustment screw, calibration screw on the back. I thought that meant you need to calibrate but these pens this being one of them are the only ones close to real and I got three of the same type, and they all ready less than 10 PPM apart which is fine for me. I can also calibrate them all the same which is fantastic as well

It works well and is easy to use. I have no way of knowing if it's accurate but I will assume it's close enough.

Bought this as part of my kit to test potential customer's water. This works very well showing the hardness in the water. It's easy to use and read results. You can push a button and it saves the reading, so it doesn't go away when you take it out of the water. Nice piece of equipment for water testing

great