What is MTDS in Water Purifier? Full Guide on How it Works

What is mtds

There is a lot of confusion among buyers when it comes to home and kitchen appliances. At homeguide, we have explained most of the terms used in water purifiers as we specialise in home appliances.

If you are searching for water purifiers, you might have come across several terms. One such term is MTDS. One of our readers asked us to explain the meaning of this term and its pros and cons. Hence we bring you this post.

Here, we will go at length to explain the meaning TDS, MTDS and their working. Also, do not forget to take a look at top rated MTDS water purifiers for you to consider. The list is curated by putting in hours of research for your convenience.

What is MTDS & How It Works

Full form of MTDS is Manual Total Dissolved Salts controller or simply Manual TDS Controller. MTDS is a a screw-based device that controls the level of salts and minerals in the purified output water. It works as a bypass valve which takes some amount of source water bypassing RO membrane to the output water, which is then filtered through a UF/MF membranes.


Now, if you are wondering what is TDS, then don’t worry, we will explain in detail. TDS or Total Dissolved Salts represent the amount of inorganic salts and organic matter present in water. These are calcium, magnesium, sodium, potassium and carbonate, hydrogen carbonate, sulfate, chloride and nitrate etc.

The catch is, TDS can be harmful at lower levels as well as at higher levels. Low TDS means that the water is devoid of essential trace elements, while higher TDS means that the quantity of these elements can be harmful to the human body. Both scenarios must be avoided. Hence MTDS becomes necessary.

MTDS device works in the principle that if some amount of impure water is added back to extremely purified RO water, it will add back essential salts and minerals to the water. Also, since the impure water quantity is low, it will not be harmful to health.

how mtds works
TDS Controller is same as MTDS

As you can see, MTDS device has two inlets and one outlet. One inlet is connected to the RO water, while other inlet is connected to UF/MF purified water (which is not as pure as RO). This means that in this device, slightly impure water from UF/MF is added back to RO water.

Hence, if you increase the UF purified water, the level of TDS will increase and if you decrease this water, the TDS will decrease.

This level of this UF/MF water entering the device can be controlled by a small screw attached to the device.

Advantages of MTDS

  • Biggest advantage of MTDS is that it ensures essential elements such as calcium, magnesium, potassium etc. are added back to the water.
  • Another advantage of this device is that you can adjust the level as per your preference. Mineralizers do not give you this ability, which can result in more than required dosage in case of mineralizer based water purifiers.
  • Another big advantage of MTDS is that unlike a mineralizer, it adds back all the minerals in the water. Mineralizer on the other hand only adds back few minerals such as calcium and magnesium.
  • MTDS is quite cheap and can be procured easily either online or from retail shops.
  • MTDS is a long lasting device that does not easily gets broken or need any repairs. Also, there is no need to replace it from time to time.
  • MTDS also improves the taste of water as it keeps the TDS at ‘natural’ levels. RO water with very low TDS tastes unnatural or even bitter because we are not used-to to this type of water. Hence, MTDS imparts taste to water.
  • One advantage of this device is that it is easy to use if you know how to remove the side panel. All you need is a screw driver. Just remove the outer casing of the water purifier by unscrewing the bolts and access the MTDS device.

Disadvantages of MTDS

  • Biggest disadvantage of MTDS is that it is not ideal for use if your water has heavy metal present. This is because the small amount of impure water will add back heavy metal to the purified water and heavy metals are harmful even in small quantities. In this case, you will have to go with water purifiers with mineralizers.
  • MTDS is not suitable for water with very high TDS. In this case, its better to opt for a mineralizer-based RO water purifier.
  • Another problem with MTDS is that if you do not know how to remove the side panel, it can be a bit difficult to change the TDS of water.
  • MTDS is a completely manual method of controlling TDS, hence there is always time and effort involved in regulating the TDS levels.

How to Increase Or Decrease TDS with MTDS

Increasing or decreasing the TDS level of water is not difficult with MTDS. All you need to have is a screwdriver that fits the size of the screw attached to MTDS.

Here are the steps to follow to change the TDS levels with MTDS:

  • First of all, open the outer cover of your water purifier. This is needed because most water purifiers with MTDS house the device inside the outer cover.
  • Find the screw on the MTDS.
  • Revolve the screw clockwise to decrease the TDS of water.
  • Revolve the screw anti-clockwise to increase the TDS of water.
  • Attach the cover back.

Also, please keep in mind that it is always a better idea to get your MTDS adjusted with the help of installation technician because opening and closing of water purifier cover can be difficult sometimes.

Ideal Level of TDS in Water

It is important to note that MTDS is necessary only in RO water purifiers. This is because RO depletes the TDS of water greatly, hence it needs a TDS regulation mechanism. That’s why TDS is necessary in RO water purifiers.

Now the question is what is the ideal level of TDS in water? India’s BIS recommends TDS level of less than 500 for drinking water. You can get a TDS meter in a couple of hundred rupees in the market or online easily. Once you have the device, it becomes easy to regulate the TDS levels.

This table clearly explains the water purifier type based on the TDS level.

TDS LevelPresence of Heavy MetalIdeal Water Purifier
Less than 500 PPMNoUV + UF/MF
Less than 500 PPMYesRO + UV + UF/MF
More than 500 PPMNoRO + UV + UF/MF
More than 500 PPMYesRO + UV + UF/MF

In short, you should go for UV + UF/MF water purifiers if the TDS is low and there is no presence of heavy metals. This is because heavy metals are toxins that are extremely harmful to our bodies even in very low quantities. Hence you should purchase RO water purifier if there is any history of metal poisoning in your area.


MTDS vs Mineralizer: Which is better?

MTDS and mineralizer are two different technologies with slightly different working. MTDS adds back impure water (with minerals), while mineralizer adds only pure minerals through a cartridge. MTDS is cheap, does not require constant replacement and allows for adjusting of TDS.

On the other hand, mineralizer is expensive, requires replacement once the cartridge is empty and does not allow adjustment of minerals. Hence, MTDS is better than mineralizer in most cases. Only when water contains heavy metals, mineralizer should be used because heavy metals are harmful even in small quantities.

Allows you to control the output TDSYou cannot modify TDS of output water
InexpensiveMore expensive
No need to replace from time to timeHas to be replaced every 1 to 1.5 years
Adds all the mineralsAdds only few minerals

Frequently Asked Questions

TDS vs MTDS: What is the difference?

TDS controller is the brand name used by Kent and other water purifiers, while MTDS brand name is used by Eureka Forbes water purifiers such as Aquasure and Aquaguard as well as HUL.

What is the difference between Taste Adjuster, MTDS and TDS Controller?

Taste Adjuster, MTDS and TDS Controller all are the same devices. Different brands use different names as per their convenience!

Should I buy a water purifier with or without MTDS?

MTDS is an important part of any RO water purifier because it balances the TDS level. It is necessary because RO process removes all the essential minerals from water, which the MTDS devices adds back. However, non-RO water purifiers do not need MTDS because no minerals are removed from water. Hence, you should buy water purifier with MTDS only if it is an RO.

Is there any automatic TDS controller?

No. All TDS controllers (including MTDS) are manually adjusted.

Best MTDS Water Purifiers

Since MTDS term is used by Eureka Forbes, MTDS water purifiers are Aquasure and Aquagguard water purifiers.

Eureka Forbes is one of the most popular brands of water purifiers in India. It is part of respected Shapoorji Pallonji group and was launched in the year 1982. Eureka Forbes launches some of the water purifiers directly through e-commerce channels, therefore it is recommended to view water purifiers online if you want to get a full list of new water purifiers that get launched

Aquaguard and Aquasure Brands

Aquaguard and Aquasure brands are 2 popular water purifiers brands from Eureka Forbes.

Aquaguard is a popular brand that was one of the first popular water purifiers in India. Owing to the popularity of Aquasure, Eureka Forbes launched Aquasure brand inAquasure is a more recent brand and its value proposition focuses more on affordability as compared to Aquaguard.

We bring you a list of MTDS water purifiers from Aquasure and Aquaguard.

#1 Aquaguard Aura RO+UV e-boiling + MTDS Water Purifier

9.8 ✔️

Launched in: 2020

User Rating: Excellent

Why Recommended?: 8 stages of purification ensures best output

Aquaguard Aura has all the advanced features required for best water filtration that comes with copper technology. Its sleek design is an added bonus and will go well with modern home decor.


  • It has a storage capacity of 7 L, which is decent for a medium sized household
  • It has feature to boil water for 20 minutes. This is a unique feature which you will not find in many other brands of water purifiers. Benefits of drinking boiled water are well documented.
  • It comes with inbuilt taste controller (MTDS). This will give you good taste no matter what is the source of water for your filter.
  • Aquaguard Aura also helps in essential mineral retention with help of its mineral retention technology
  • This filter contains copper cartridge inside it. This cartridge regularly dissolves copper ions into the water. Copper is an essential trace element necessary for good metabolism.


  • It has a sleek design and metallic finish. Very suitable for modern homes.
  • Mineral Guard technology retains Calcium and Magnesium in water


  • If inlet water pressure is low then you will have to buy additional Booster Pump. Which you can ask Eureka Forbes technician to arrange.

Check Price on Amazon

#2 Aquaguard Marvel RO+UV+MTDS with Active Copper Water Purifier

9.7 ✔️

Launched in: 2020

User Rating: Very Good

Why Recommended?:
Active Copper & Mineral Guard technology

Aquaguard Marvel gives best filtration and it also has all the key technologies necessary. Its body is made up of food grade plastic and is robust and durable.


  • It also has a multi-stage filtration process that gives excellent water output
  • Just like Aquaguard Aura (first in our list), this water purifier comes with Active Copper tech to give you goodness of copper
  • It has Mineral guard technology to retain essential minerals such as calcium and magnesium
  • UV e-boiling technology boils the water for 20 minutes be during the end of filtration process.
  • It also has inbuilt tase adjuster that helps in removing any foul tase and smell as well as adjusts the taste irrespective of the source of water.


  • It is made of food grade plastic. This plastic is has good durability and strength.
  • It has all the major proprietary technology developed by Eureka Forbes


  • This might require booster pump in case water of less water pressure

Check Price on Amazon

#3 AquaSure Delight RO+UV+MTDS Water Purifier

9.4 ✔️

Launched in: 2019

User Rating: Very Good

Why Recommended?: Highly effective 6 Stage purification

This is a very popular water filter because it comes with almost all the goodness of Eureka Forbes except active copper and very good capacity of 10 L


  • It has a capacity of 10 L
  • It has chemi-bloc that reduces excess chlorine and other bio-impurities
  • It is suitable for water with PPM upto 2000 ppm and you can adjust TDS levels in water manually
  • It comes with MTDS. This will help in regulating taste of water
  • It also has mineral cartridge. This feature is available in all the major Eureka Forbes water filters.
  • It also has a UV chamber for UV filtration process. This helps disinfect water from germs and viruses.
  • It has LED indicators to signal when the tank is full. It also has indicators for power-on status and purification process.


  • It comes with chic design and at attractive pricing.


  • It does not have active copper technology

Check Price on Amazon

#4 AquaSure Amaze RO+UV+MTDS 7L Water Purifier

9.7 ✔️

Launched in: 2019

User Rating: Excellent

Why Recommended?: Dual purification with RO+UV+MTDS

This water filter comes in sleek design and has decent features. If you are looking for goodness of Eureka Forbes then you can consider this product


  • It has storage capacity of 7 L which is not very different from other water purifiers in our list
  • This product has multi stage purification with RO and UV technology. It also has taste adjuster to infuse enhanced taste in water
  • This water purifier comes with energy saving mode. This will switch off the power supply in when the storage is full. Thus saving energy.
  • It has LED indicators to signal when the tank is full. It also has indicators for power-on status and purification process


  • This water purifier has sleek design that will go well with modern house decor.
  • Energy saving mode is good for saving on power consumption
  • It has a long lasting cartridge. The cartridge has a life of around 6000 L.


  • No major cons

Check Price on Amazon

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