Xiaomi Mi TDS Pen Review – The Fastest & Most Elegant TDS Pen Under $12

All it takes 1 click and 1 second to check the quality of water!

The world is getting smart and the quality of life is increasing year after year. Most of us focus on healthy living with an active and healthy lifestyle. We select the best things suitable for our health. Such is a TDS Pen which is used to check the quality of water. However, the question is where to find ‘The Best’ TDS Pen? Today, we bring you another addition to the Xiaomi family, our protagonist ‘Xiaomi Mi TDS Pen’. Thanks to its premium waterproof design, the quickest and the accurate response that it has forced me to do a Xiaomi Mi TDS Pen review.

One might question that why we need a TDS checker as the water in our home is already treated. Well, it’s simply to assure yourself that the treated water has the water quality as mentioned or do we need to change the water filters. Most importantly, it’s used for the tourists or travelers who have to travel places and drink water from there. It’s also used to check the water quality of the fish tank.

So, is the Chinese Xiaomi Mi TDS Pen worth buying under a given price tag of $12? Is it really that accurate? What impurities does it find? Let’s get to know everything about this new TDS Pen in this Xiaomi Mi TDS Pen review:

Can We Trust Xiaomi?

If you are a techie, there’s no way that you haven’t heard of Xiaomi. Yup, it’s the famous smartphone manufacturer from the Chinese land which introduced budget-friendly and premium phones such as Redmi Note 5 and Mi 8, respectively. However, Xiaomi isn’t limited to smartphones. Starting from Mainland China and moving to the whole globe, the company isn’t limited to smartphones but also provides a variety of consumer electronics, home appliances, and so on, based on the term ‘Smart’.

One thing you should know that whenever it comes to buying something from China, Xiaomi is the first on the list that you should consider buying. There’s not even a single product which has a poor user-satisfaction. Each product is affordable in its own category and each of them is made of the finest quality. Xiaomi Mi TDS Pen is not an exception.

Xiaomi Mi TDS Pen Review – Simply the Most Premium TDS Pen to Date!

The Unboxing

The Mi TDS Pen rest inside a rectangular white box. Like most of Xiaomi’s product packaging, the white box has the product illustration on the front, and some silver-colored writing on each side reflecting in the light.

Xiaomi Mi TDS Pen Review 2

Sadly, since it’s a Chinese product (no global version), the writings are in Chinese. The method to use the TDS Pen is written on the back in Chinese, but don’t worry I will help you in knowing how to use it in this Xiaomi Mi TDS Pen review.

Xiaomi Mi TDS Pen Review 1

You can simply have the first impression of the Mi TDS Pen just by sliding the tray. However, when I tried this, the first impression ruined as the whole tray was out and the Mi Pen was still inside the box. Opening the box, and jerking is much better as the product simply slips out the box.

Xiaomi Mi TDS Pen Review 3
Xiaomi Mi TDS Pen Review – First Impression

As far as the accessories are concerned, Mi TDS Pen doesn’t have anything extra since the only thing we need is the pen and the instruction which are written on the box.

However, the manufacturer is generous as it provides two AG13 LR44 button batteries already embedded in the Pen. So, just open the box, and start using it.

Xiaomi Mi TDS Pen Review 15

Design & Appearance

To be honest, Xiaomi Mi TDS Pen is the most beautiful TDS Pen we have ever seen. Since the TDS Pen are mostly used commercially, the design of a TDS meter is really ugly. However, since Xiaomi somehow manages to make a simple product look extraordinarily charming when it enters the Xiaomi tag. It has a pure white color which glitters in your eyes.

Xiaomi Mi TDS Pen Review 4

Most of the TDS pens have a rugged body and a non-symmetrical design, whereas Xiaomi Mi TDS Pen fascinates us with the premium plastic built offering a boundless holding experience. You simply know that you are holding a real Xiaomi product since it’s too smooth and comfortable. From a distance, you never know that one is holding a test meter or a stick.

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It’s perfectly aligned and symmetrical. The curvy borders further exaggerate its beauty. However, I noted that the smooth and silky body is slightly slippery and becomes more slippery if there’s water on the surface. However, the product is durable though molded from plastic. Even it was working perfectly after dropping it 2 times accidently.

Xiaomi Mi TDS Pen Review 6

Talking about the physical factors, the Pen occupies a space of 9.00 x 5.00 x 4.00 cm and weighs around 30 grams. In simple words, it’s almost square-shaped, equal to iPhone SE in length. In comparison to other $15 TDS pen, this one is 2x lesser the size and weight.

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Another aspect I loved about this TDS Pen was that how easy it was. Simply remove the top cap and you have the two button batteries visible and easily replaceable.

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Xiaomi has kept it simple with only one button to operate it, while we see multiple buttons on other TDS pens.

As this pen checks the water quality, the plastic chassis is IPX6 certified making it splash-proof, not waterproof. Remember that it’s not IPX7 or IPX8, so never try to dip it completely in a liquid container.

Ending this section, I probably haven’t witnessed a $15 TDS pen that is as elegant, comfortable, and exceptional as the Xiaomi Mi TDS Pen.

Screen & Display

On the front, near the tail, we have a nice 2.54 cm (1-inch) section covered with glass. Underneath is the 2 cm screen. The screen looks fine showing three figures along with the unit.

Xiaomi Mi TDS Pen Review 5

However, one of the down points of this product is that it’s hard to see the display especially if you are in a low light. At one angle the screen shadows and at another angle, we see slightly doubled figures. I don’t know what the reason is but for a popular brand as Xiaomi, they should have added a black light under the display like in watches or made the figures illuminating. You have to be too close to see the reading. You simply can’t remove it from the water sample, as the reading will return to ‘0’. Maybe, the display was like this, to improve the battery timings of the TDS Pen.

Though nothing to complain as most of the TDS has a much worst display then this and I haven’t heard any TDS with a backlight display as well. Under $12, honestly, nothing to grumble.

How to Use / How to Replace Batteries?

Here I kept my promise, I will teach you the basics of this TDS Pen. This Pen interface is not a big deal. Here’s how to use it:

  1. Check if the batteries are placed correctly
  2. Press the TDS button near the display to turn on
  3. Simply remove that transparent cap at the bottom
  4. Place the electrode head (from where you removed the cap) in the liquid container
  5. Make sure that only the bottom end is submerged in water, not the whole body
  6. Note the value on the screen
  7. Press the button again to turn it off

Xiaomi mi tds pen value range

To replace the batteries:

  1. Remove the cover from the tail
  2. Remove the two AG13 LR44 button batteries
  3. Note the placement of batteries on the chassis (the positive end on the right side, and the negative end on the left side)
  4. Check if the pen is working by pressing the TDS button to turn on the display
  5. If not turned on, try placing the buttons the correct way as said above

I notice that the design and layout of the TDS Pen reflect more on the personal/domestic use not the industrial. It’s simply a Dummy-proof operation.

Responsiveness & Accuracy

The best part in this Xiaomi Mi TDS Pen review is this one. In comparison to other TDS pens, Xiaomi Mi TDS Pen is way responsive. I noted that it only took less than a second to measure the quality of water hitting the titanium TDS Probe, which is super-fast. Moving it in the liquid caused the values to change quickly but were constant when the pen was stable. After removing the pen from the liquid, it took only 2 seconds to reset to 0. That is why I had to note the reading while it was in the container which was slightly difficult as I have already told you about the screen and display. However, it’s the same effort to note readings on any TDS pen available.

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Moving to the accuracy of the pen, it has an error range of +- 2%. In contrast to the $15 TDS pen, the error range is 1% lesser, which is means are it’s slightly accurate than most of the TDS water quality checkers in this range. I even conducted a few tests to check if it was that much accurate as advertised.

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Figure 2


Figure 1 and 2 shows the readings from groundwater. It’s not pure though but safe to drink. One should understand that the 190 ppi result was because of the minerals in the water. Meanwhile, the water didn’t have the other two types of impurities.

Xiaomi Mi TDS Pen Review 11 Xiaomi Mi TDS Pen Review - Dirty water

Now in the same water, I added a bit of dust and the value increased drastically to 248ppi since the TDS Pen detected some solid impurities in the water. But it’s logical that the value still didn’t surpass 300 because the Pen can only detect the three types of impurities which don’t include dust particles (as dust particles in water) and can give the readings based on these three types, not any other.

More interestingly, it has automatic temperature calibration which allows you to test the boiling water, tap water, and cold water at the same time.

The Limitation

Let me tell you the limitation of this TDS Pen (of course a $12 TDS pen as limits). The maximum ppi value it can obtain is 999 ppi which are enough to determine 5 stages of water. It can detect:

  • Soluble salts such as calcium and magnesium
  • Ionic organic compounds like Ammonium Acetate
  • Heavy metal ions like zinc, lead, and copper

It can’t detect:

  • Chlorine concentration
  • Bacteria concentration

Before ending the Xiaomi Mi TDS Pen review, one thing you should remember that the mineral water has a value between 100 – 199 ppi. It’s not that it’s contaminated but has mineral salts in it. So I hope you don’t through away that water or think that Mi TDS Pen is crap. If you want to get the lowest value, try testing that distilled water coming out of your AC’s outdoor.

Specification Sheet
ModelMi TDS Pen
Dimensions9.00 x 5.00 x 4.00 cm
Weight30 grams
Responsiveness1 second

Pros & Cons


  • Solid and elegant built
  • Dummy-proof one-click operation
  • Easily removable batteries
  • Highly responsive and accurate than others
  • Great Price/Performance ratio


  • A bit difficult to note the readings from the display
  • Can’t detect chlorine, dust particles and bacterial content

Our verdict

If you are simply concerned with checking the soluble impurities in the water and not the chlorine and bacterial content, Xiaomi Mi TDS Pen should be your first choice. Why? The trust of Xiaomi, great design 1-click operation, highly responsive, and a stupendously low price make it a quick sell out.

Price & Availability

If you are interested you can buy Xiaomi Mi TDS Pen on Gearbest for a price of $11.64. It’s only available in white color. Here’s the link to the store:



Started blogging at the age of 18, Roman is a techie with 3 years of blogging, SEO, and Wordpress experience, totally opposite of his health & nutrition career. He is a die-hard Xiaomi fan and an avid gamer, working hard to provide valuable information regarding Tech & Gadgets.

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