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HM Digital HMDCOM100 Waterproof EC/TDS And Amp Temperature Combo Meter

Free shipping on orders over $29.99

$52.99

$ 27 .99 $27.99

In Stock

About this item

  • plastic
  • Imported
  • 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


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.


Ted Wu
2025-09-05 17:36:02
Priced at 60 is darn good for what it is.Measure a bit slow for some liquid at different temperature however according to manual it is to be expected up to 5 min for the first read of that temp and liquid type.Virtually tough but it's not a hammer so dont abuse it keep it in it's case. It's not a PH meter so I dont see you have to keep it moist at all time.Shakes dry for storage fast and easy.It has a fast self calibration for use though I have not had the need to use it yet.Has both Fahrenheit and Celsius read, also measures micro siemens.Easy battery exchange.ConclusionFair construction, reasonable priced, exchangeable detector heads and decent accuracy outta factory.
R. J. W.
2025-08-24 13:08:47
I happy with this device. I had purchased a less expensive model, but it failed and I returned (which was easy to do). I use it for my hydroponic gardens. But also like using it to test my tap water, my Brita filtered water and purchased drinking and distilled water. You can learn a lot about your water sources this way. Would be good to have in a disaster emergency kit too. It's very sturdy and it's easy to use. Recommended.
Customer
2025-08-10 10:53:07
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.
Placeholder
2025-07-13 17:41:37
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.
Sand Spider
2025-07-06 13:55:25
Out of the box and it didn't work. Checked the batteries and they had started to explode. Change the batteries and recalibrated it and it is working. Will come back and re-review after a week.(Update) Still works like a champ and is still holding calibration. I would give it 5 stars if it wasn't for that battery issue I had.
Mike
2025-07-05 12:13:41
This EC meter is great for a range of applications. I have used it for water quality testing, horticulture, and for experimentation. Also did I mention I have been using the same meter for a little over 7 years with zero malfunctions. All I've had to do is chanhe the battery and clean the probes every so often. I love that it's waterproof since I have dropped it in water a few times amd the seals are still holding up even after 7 years of use. Would definitely recommend this meter.
Rich Carman
2025-06-15 11:38:34
I was excited to get this unit and it seemed like a great product, however, after one use I turned it off to store it and the next time I went to use it the batteries are dead! I thought "operator error" and replaced these very expensive batteries and it began working again. I used the device, very diligently cleaned and turned it off, making sure to show my brother that I had turned it off. I went to use it again and the batteries are dead once again! Unfortunately I don't use it often enough that I can send it back for replacement so my advice is don't buy this product! I found one user review that had the same issue.
MIDEE
2025-05-18 16:35:34
Easy to use, accurate to industry standards of +/- 2%
Didou 74
2025-04-25 16:38:30
Parfait
F. D.
2025-03-29 15:56:16
Con 7 meses de vida se descompuso.
Ice maker
2025-03-07 15:17:12
As a curling ice maker it is imperitive to use water that is as clean as possible. This TDS meter is quite expensive but extremely accurate. I am very satisfied with the quality of this product.
Alejandro C.G.
2025-03-04 12:36:48
Es un medidor TDS profesional, calibrable y con electrodos de platino recambiables. No es un juguete. Si necesitas un TDS fiable, este es suficiente hasta para una tesis de investigación. Yo lo uso en acuarios porque es calibrable y la temperatura y tds me han dado exactos, contrastados con un instrumentos de laboratorio que solicite para comparar.
L. A. Fenerty
2025-02-02 14:57:56
Use this for TDS testing on the work boiler. Works well and is accurate.
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