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HM Digital TDS-EZ Water Quality TDS Tester, 0-9990 ppm Measurement Range , 1 ppm Resolution, +/- 3% Readout Accuracy
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- Economy model that is ideal for end-users. Highly efficient and accurate due to its advanced microprocessor technology.
- Hold Function: saves measurements for convenient reading and recording.
- Auto-off function: the meter shuts off automatically after 10 minutes of non-use to conserve batteries. Display: large and easy-to-read LCD screen.
- Measurement Range: 0-9990 ppm. From 0-999 ppm, the resolution is in increments of 1ppm. From 1000 to 9990 ppm, the resolution is in increments of 10ppm, indicated by a blinking 'x10' image. Fun, translucent blue housing that's very strong and durable.
- TDS-EZ meters are calibrated with a 342 ppm NaCl solution. Meters can be recalibrated with a mini-screwdriver. Includes a TDS chart sticker on the back of the meter that explains TDS values.
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Top Customer Reviews
Update: I have realized that there is a HM Digital TDS-4 Total Dissolved Solids Pocket Size Meter unit available on amazon for just a couple of dollars more than this unit. From what I can gather, the TDS-4 is essentially the same unit but has temperature compensation circuitry that does not exist in the HM TDS-EZ. I did a simple test to see if I could quantify the temperature effect. The effect appears substantial. I am reducing my rating from 5 down to 3. Here are my results using the same sample of tap water at different temperatures:
54 degrees: 220ppm
100 degrees: 404ppm
112 degrees: 434ppm
130 degrees: 540ppm
Plotting this on a graph reveals a linear variation.
I read all the specs for each tester I found and it came down to this TDS-4 and the TDS-EZ. The determining factors were its accuracy and ATC. The TDS-4 has a stated accuracy of +/- 2% as opposed to the +/- 3% of the TDS-EZ. The TDS-4 has ATC (Automatic Temperature Compensation) which comes in handy since water can be different temps. Each had the same hold and auto-off function and read in 1 ppm for the first 999 and 10 ppm for 1000 - 9990.
One disappointment I had with the TDS-4 was that it didn't have a "How pure is your water?" chart on the back like the TDS-EZ. It's not hard to remember what's on the TDS-EZ chart, but would be a nice-to-have. Instead I just remember that 0 to 50 is what my RO system should be at, 50 to 100 are carbon filters, 100 to 200 is hard water, 200 to 400 is average tap water (200 to 300 being marginally acceptable drinking water), and that 500 is the EPA's max level it should be (Source: TDS-EZ chart).
I originally ordered the TDS-4 to test our new RO (reverse osmosis) under counter filtration system (Watts Premier WP-4V). Now for my experience with the TDS-4, when I received the unit from Amazon I immediately tested my RO system first (29 ppm), then my tap (251 ppm), and finally RO water from a local watershop (2 ppm). My RO system was in mid-range of the 0 to 50 acceptable for RO systems, my tap was in the mid-range of acceptable tap levels of 200 to 300, and the water from the watershop was almost pure water.Read more ›
The sensors measure the Total Dissolved Solids (TDS), which are the total amount of mobile charged ions, including minerals, salts or metals dissolved in a given volume of water in parts per million (ppm). However, I found out that water from the same source will measure differently when the temperature is different. For example, a room temperature water measured at 150ppm, but 110ppm when cold and 192ppm when hot. I thought its interesting.
I like the fact that in the back of this device, they put this sticker so you don't need to memorize anything:
How Pure is Your Water?
0-50ppm = ideal drinking water
50-100ppm = carbon filters, springs
100-200ppm = hard water
200-400ppm = average tap water
and so on
It also has protective cap to cover the sensors (not shown in the picture). It's factory calibrated and is ready to use, but can be re-calibrated with NaCl using a small Phillip screwdriver. Battery lasts for about 1000 hours and the instructions are clear with reference to the website if more information is needed. Overall, it's a 5 star item. No more guessing now!
Ok I cannot put the web URL in, Amazon does too good of a job finding that you have put a web link in. I will place the URL location vertical:
Also you should know the TDS-3 does everything the TDS-4 does and it also reads out temperature, TDS-3 is not a slim design though.
Most Recent Customer Reviews
Accidentally dropped this in my hydro reservoir. Took it out and it doesn't work any longer. I don't believe this product is waterproof. Read morePublished 1 day ago by Jeremy G Oberg
Didn't realize that it offers no specific info on water deficits, merely a report of good or bad.Published 2 days ago by Waimau
I think it's a must have if you do not have control over your water. My city water changes all the time. Because of the wild fluctuations I started purifying my own water.Published 2 days ago by Joshua
Nice and simple tool, good to give concerned customers an idea of water quality.Published 2 days ago by Marco