It is also interesting to note that this same feature is sometimes marketed as ‘TDS Modulator’ by some water purifier brands. However, TDS Controller and TDS Modulator is one and the same thing and there is no functional difference between the two.
What the heck is this TDS Controller/Modulator?
The following text will answer all your questions about TDS controller in an easy and user-friendly manner.
Let’s begin then…
What is a TDS Controller?
In simple terms, a TDS Controller is a device that controls the TDS of water. Unlike the filters, cartridges, and membrane(s), TDS Controller does not filter or purify the water in any way.
The image above shows a typical TDS controller, as you can see this is a small device. This is quite inexpensive and costs roughly around Rs. 50 only.
How TDS Controller Works?
TDS Controller is basically a manual device which consists of two water inputs, one water output, and a TDS Control screw.
Water Input 1: Purified water output from the RO membrane
Water Input 2:
a) Purified Water from Activated Carbon Filter in case of RO+UV+TDS Controller Water Purifiers
OR
b) Purified Water from UF Membrane in case of RO+UF+UV+TDS Controller or RO+UF+TDS Controller Water Purifiers
Water Output: Mix of two water inputs in the required ratio.
TDS Control Screw: TDS Control screw controls the TDS value in output water by manually adjusting the flow of water from the two water inputs.
I) If TDS needs to be reduced then the flow of input water from the RO membrane is increased and the flow of input water from Activated Carbon Filter or UF membrane is reduced.
II) If TDS needs to be increased then the flow of input water from the RO membrane is reduced and the flow of input water from Activated Carbon Filter or UF membrane is increased.
Simply, Turn the screw clockwise to reduce the TDS level or anti-clockwise to increase the TDS level.
Please note, in most RO purifiers, TDS Controller is located inside the assembly along with all other RO parts. So for adjusting the TDS level, you will have to first open the outer cover.
However, if you are not comfortable doing this, we recommend getting this done from a trained professional.
Recommended TDS Level in Drinking Water?
You should adjust the TDS controller such that the TDS level of purified water is between 80 to 150 ppm.
Need and Benefits of TDS Controller?
Natural water contains several essential minerals like Calcium, Magnesium and may also contain harmful impurities like heavy metals, fluorides, and arsenic.
These minerals and heavy metals are what constitute ‘Dissolved Solids’ in water. The level or the presence of these Dissolved Solids in water is commonly referred to as TDS (Total Dissolved Solids) level of water.
The presence of minerals like calcium and magnesium in small quantities is what makes the drinking water healthy and it is very essential that the drinking water contains these minerals.
RO Membranes usually removes around 90% of dissolved solids from the input water, and that includes essential minerals.
What this essentially means is, if the input water does not have high TDS then chances are the RO Membranes will reduce the level of essential minerals to a significantly low level making the water unhealthy and not fit for drinking.
This is where the role of TDS Controller comes into effect. As detailed above, in such a scenario when the TDS level of the input water is not so high, TDS Controller can be used to increase the TDS of purified water to a healthy level.
TDS Controller is basically used to increase the level of essential minerals in the purified water.