What is the purpose of the hard water indicator in a drinking water bottle?
Hard water does not always lead to kidney stones, but it can increase the risk of one. Very hard water with salt levels above 400 ppm can increase the risk of kidney stones. In most cases of kidney stones, the blood in the human body, due to certain congenital problems, begins to absorb more calcium from water and food than is actually needed. As a result, excess calcium is deposited on the walls of the kidneys during the excretion process.
By drinking high salt water, we put ourselves at risk of becoming one of the 30 million people in the United States suffering from kidney stones.

The bottle contains a lid with well-known devices for convenient drinking of water and a flask made of ecological plastic. A measurement and control unit is screwed into a plastic flask. The conductivity sensor is located on the upper surface of the measuring block. The power supply of the bottle is Lithium Metal batteries with a voltage of 3 V.

The bottle works like this:
– after filling the bottle with water, press the power button;

– if the salt content is less than 200 ppm, then the bottle glows green,

– when the salt content is more than 200 ppm, the bottle glows red.

– the glow of the bottle continues for 1 min, after which it turns off.

– to re-determine the salt content in the water, press the power button.