Some of the Water Purifier companies are misleading the Customers. They are stating that the Tap water and bottled drinking water contains unwanted impurities. for which they are performing an experiment in-front of the customers. (actually this is only an electrolysis)

They used to take the tap water/Bottled water in a glass and their water in another glass (the water getting from their water purifier) . Then they put electrodes to both glasses which will be connected to a electric line . after 2/3 minutes the bottled water/tap water colour get turn brown . but the water from the water purifier will the same as before.

Now they starts to convince the customer that this brown color is due to the invisible dirt present in the water
or more minerals are present in the water (depending up on the situation and customers) .

Actually the brown color is due to Total dissolved solids (TDS) present in the tap/Bottled water . WE need some mineral in the drinking water water

These Water Purifier companies using electrolysis method to do confuse the customer