Difference between TDS Controller vs Mineralizer

While searching for best water purifiers in India, you would have come across terms like TDS controller vs mineralizer used in conjunction with the RO water purifiers.

We already know that the RO water purifiers use micro sized semi-permeable membranes to filter out impurities from drinking water. However, in addition to removing impurities, RO filter membranes also remove the essential minerals and salts present in water which are required by the human body. These salts and minerals are not only essential for body, but also provides taste to the drinking water.

If the drinking water doesn’t have any essential minerals, then it will have a very bland taste and is also not healthy for human consumption. In order to preserve or restore the essential minerals in water, the modern day RO water purifiers use either TDS modulator or mineralizer in combination with the RO filter.

In this article, we shall take a look at how the TDS controller and Mineralizer work, and we shall also provide recommendations around choosing TDS controller vs mineralizer.

TDS Controller

RO water purifiers are capable of removing 90-95% of TDS from the source water. The TDS of RO purified water is generally around 50-100. We have already seen in this article around TDS of water, that the TDS value below 150 isn’t great for human consumption.

Therefore, in order to regulate the TDS of water in RO water purifiers, a special device called a TDS Controller/ Modulator is deployed which helps in regulating the TDS of water to around 200-300 PPM. The TDS controller allows flexibility to alter the TDS of water as per the taste requirement.

Working of TDS controller - TDS controller vs Mineralizer
  • The input water is split into two parts – one part goes directly into the RO filter and the other part bypasses the RO filter.
  • The water passing through the RO filter is purified completely and has a very low TDS value.
  • The other part which doesn’t pass through the RO filter, is passed through UF filter to remove the turbidity, bacteria and cysts etc. However, the TDS of this part of the water is relatively higher as compared to the water passing through the RO filter.
  • The TDS controller controls the proportion of the water passing through the RO filter vs the other part.
  • The water output from the RO filter is then mixed with the non RO purified water to regulate the TDS. How the mixing happens can be controlled using the TDS controller valve.
It is worth noting that the purifiers which deploy TDS controller are generally paired up with UV/ UF filters as well. This is important because part of the water doesn’t pass through the RO membrane and hence contains some level of impurities. The UV and UF filter are essential to make sure that the residual impurities are removed by the UV/ UF water filtration.

Advantages of TDS controller

Flexibility: TDS controller allow flexibility around adjusting the TDS of water as per taste. You can even close the water coming from part 2 ang get 100% RO purified water.
Economical: TDS controller is a very cheap and readily available device which has a long life and doesn’t require frequent replacements.
TDS controller replenishes lost minerals from water in a natural way and doesn’t rely on mineral cartridges.

Disadvantages of TDS controller

The only disadvantage of using a TDS controller is that the water purified with TDS controller is not 100% pure. Reason being, that part of the water is not passed through the RO membrane and might contain metal impurities from the source water. To compensate for this, the RO water purifiers with TDS controllers come with UV and UF filters as well.

TDS controller are often refereed to by the name TDS modulator as well because it controls as well as modulates the amount of TDS in water.


Mineralizers are relatively new technology used in water purifiers to enrich and boost RO purified water with essentials minerals and salts which get lost during the RO filtration process.

Water purifiers fitted with mineral cartridge allow the RO purified water to pass through the mineral cartridge. As the water passes through the mineral cartridge, it extracts essential minerals from the mineral balls present in the mineral cartridge.

Mineral cartridge - RO water purifiers

It is extremely important to make sure that the mineralizer cartridge used is of good quality. Some mineralizer cartridge also have water energizers and PH boosters which increase the PH of water by making it a little alkaline.

Advantages of Mineral Cartridge

Water purifiers deploying mineral cartridge offer best protection against the metal impurities. Reason being, 100% of water passes through the RO membrane and the lost minerals are added back using the mineral sheet.

Disadvantages of Mineral Cartridge

Water purifiers with mineral cartridge offer no control over the TDS of water. The TDS of purified water largely depends on the source water TDS and TDS added by the mineral cartridge.
High maintenance cost:The mineral cartridge requires replacement within 6-9 months based on the usage. Therefore, it is not a very cost effective option.

Comparison between TDS Controller vs Mineralizer

TDS ControllerMineralizer
Provides flexibility in terms of adjusting the TDS of purified waterThere is no control on TDS of purified water and it can not be adjusted
TDS controllers are very cheap and have a long lifeRequires annual maintenance to replace the mineralizer and is not very cost effective
Suitable for water having TDS up-to 1000 PPM with low concentration oh heavy metal impuritiesSuitable when the source water has high TDS and high concentration of heavy metal impurities


TDS controller and mineral cartridge are both viable options which can be used to increase the TDS of RO purified water. The choice between TDS controller vs mineralizer should depend on the TDS of input water as discussed in the previous section.

Feel free to drop a comment in case you have any question and we will get back to you as soon as possible.

Related posts:


How to check TDS of water

9 Best Hair Straighteners in India


Leave a Comment