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Calcium / calcium ion in drinking water, the whole truth!

Table of contents
limescale test on water

You probably haven't noticed, it's insidious, but when we talk about mineral water, we extol the virtues of the mineral salts (calcium, magnesium, potassium...), whereas in the marketing of filter carafes, we talk about ugly limescale.

So I'm going to tell you the amazing story of this underground rock, all the way to our glasses of water, and then our bodies.

What is calcium used for?


So, as you've heard, without calcium you die, quite quickly. It's used to control muscles, form our skeleton, our nails, our teeth, etc...

It is a very common element on the planet, making up a fifth of the Earth's crust, with 3% of its mass. It is also an important element in our bodies, accounting for 2% of our weight. There are a number of mechanisms that ensure its balance, and what is certain is that we need to take in enough of it to let the body do its job of measuring it.

So, for the last 60 years, you've been told that you need to drink milk or eat cheese to do this, and I feel duty-bound to tell you that this is not true!

Why is this? Very simply, every time you drink milk or eat cheese, you are absorbing calcium, no mistake, but also animal proteins, which greatly reduce its bioavailability. The calcium content of dairy products is therefore greatly overestimated.

Better calcium in bottled water?

water in plastic bottles

A false rumour: mineral water in plastic bottles is said to contain calcium that is better for your health than that found in tap water...

This is obviously completely untrue - just imagine what a nice scientific study would be available if it were true.

This is a false rumour that has been around for some time. In reality, both tap water and bottled water contain minerals. However, the mineral content, including calcium, can vary depending on the source of the water.

In France, tap water is subject to strict quality standards and is regularly tested to ensure that it is safe to drink. In addition, tap water is often enriched with minerals to meet nutritional needs (including calcium and magnesium).

Depending on the region, tap water provides us with an average of 25% of our daily calcium intake, while the rest can be found in spinach, broccoli, cabbage, salad, almonds, etc...

On the other hand, bottled water can have different mineral content depending on the source and treatment of the water. Plastic bottles can also release chemicals into the water over time, which can cause long-term health problems. You can find out more by reading our article on the environmental impact of plastic water bottles.

So, with all this complex data in front of us, mainly from marketing, it's not easy to see clearly.

But let's continue with the calcium ion, generally collected by groundwater in calcium carbonate rocks.

tap water

What about limestone?

More misinformation: hard water contains limescale.

Of course not, tap water contains only dissolved salts (calcium and magnesium ions), no 'rocks' or sedimentary rock (tartar, aragonite, limestone), so there's absolutely no risk in drinking it - quite the contrary.

So, yes, but why do you see limescale/calcite/aragonite in your water heater, kettle or coffee maker?

This is due to the acid-base balance: when you heat water that naturally contains C02 (acid), this expels it into the air in an open environment, or forces it to micro-bubble on the walls in a closed environment, while increasing the internal pressure.

At this point, the medium becomes slightly basic (pH above 8), and the dissolved calcium begins to mutate into a solid crystalline form, such as aragonite. The phenomenon accelerates rapidly above 60°C.

It won't happen in your 38°C body!

All these phenomena can be avoided by intelligent design of household appliances and water heaters, which would only cost a few extra euros, and would make them unbreakable, or almost. For the curious and geeky, all you have to do is use stainless steel bowls or flasks, and stick a heating film on the outside. This reduces the power density by a factor of 10 to 100, and no longer creates the one-off thermal shock needed to start the reaction. If you look hard enough, there is already a water heater on the market, and soon a kettle, that combats the disadvantages of hard water.

You should also know that shellfish use this process to make their shells: they use a phenomenon called bio-mineralisation, which causes calcium and CO2 from the oceans to combine to form calcite.

A water softener to protect your household appliances?

water softener
The main argument for using a water softener to combat limescale is that it will protect your household appliances (dishwasher, washing machine), your water heater and the pipes in your home from the harmful effects of limescale. Is this really the case?
Read also: Why install a water softener?
Descaled washing machine heating element
Descaled washing machine heating element

It's highly likely that you won't! In fact, by removing the calcium from your water, the softener runs the risk of making it acidic and corrosive through the addition of salt. Is this really preferable to hard water for your household equipment?

Read also: Is there such a thing as a nuisance-free water softener?

So what's the solution? There are alternatives, which we describe in detail in our article entitled "Is there such a thing as a nuisance-free water softener?". These options won't turn your tap water into seawater and will be environmentally friendly!

What's more, if your kettle does scale, there are a number of simple tricks you can use to take care of the problem [see our article : How can I descale a kettle and extend its life?]. And if you'd like to find out more about water hardness and the difference between soft and hard water, please see our article Water hardness: What is hard water and how do you measure it at home?

I hope that after reading this article and these few tips, you will have understood that calcium is one of the pillars of our health, and undoubtedly one of the most important. So we need to stop buying polluting devices to reduce trace elements (such as water softeners) and then trying to get more of them in dairy products, which are just as heavy on the environment. Let's be proactive, let's analyse what's going on within us and around us, let's use our common sense - that's what makes for good decisions.

Our sources (no pun intended)

LaVie PURE - 1 litre

Preserve the trace elements in tap water by LaVie

LaVie® UV-A water purifiers work no filter, no maintenance and allow you to purify your tap water by 15 minutes.

They use an innovative, patented technology exclusive to LaVie®: photolysis of chlorine using UV-A radiation.

This treatment reduces chlorine and its derivatives, chemical compounds such as certain pesticides or traces of medicinesand tastes and smells that can be found in tap water, while at the same time preserving trace elements at 100%.

The result, which is of a very high quality, makes it possible to draw a definitive line under the consumption of bottled water.

The carbon footprint associated with the manufacture of the UV water purifier's aluminium tube is neutralised in just a few days of use, compared with the equivalent consumption of water in plastic bottles.

Pascal Nuti CEO of LaVie Water Purifier

Article written on 16/06/2020 by Pascal Nuti - CIO Solable - Passionate about energy, I'm constantly on the lookout for new targets for improvement, exploring cross-disciplinary paths using novel methods.

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