Minerals and electrolytes in water – what is worth knowing?

Table of Contents

• What are electrolytes in water?
• The most important ions in water
• Electrolytes and conductivity and TDS
• Water mineralization: label interpretation
• Thresholds: very low, low, medium,highly mineralized
• Sodium and the designation "suitable for a low-sodium diet"
• Taste and drinking comfort vs TDS and anions
• The impact of treatment on electrolytes
• Reverse osmosis (RO) and mineralizer
• Water softenerion exchange and sodium/potassium
• Ultrafiltration and activated carbon
• What water and filter should you choose for your needs?
• Quick indicators and measurements at home
• TDS/conductivity meter – what does it show and what does it not?
• Hardnesswater – the most important conversions
• Summary

In this article you will learn:

• What are electrolytes – and why ions determine TDS, taste, and behavior of water
• How to read labels of bottled waters and research reports (mg/l, conductivity,hardness)
• How treatment changes minerals – RO, mineralizer, softener, ultrafiltration
• How to choose a filter based on taste, household appliances, coffee/tea, and the needs of household members
• How to measure TDS and hardness at home and interpret the results

What are electrolytes in water?

Electrolytes are ions dissolved in water – positive (cations) and negative (anions). In drinking water, the dominant ones are: calcium (Ca²⁺), magnesium (Mg²⁺), sodium (Na⁺), potassium (K⁺), as well as bicarbonates (HCO₃⁻), chlorides (Cl⁻), and sulfates (SO₄²⁻). Their sum creates what is called mineralization, which affects taste, electrical conductivity, and the formation of scale.

Key thought: Electrolytes = ions. They are the ones"carry" conductivity (TDS/EC), determine hardness and whether the water is perceived as "flat," "salty," or "chalky."

The most important ions in water

• Ca²⁺, Mg²⁺ – the main components of hardness (scale deposits); influence on the taste of "fullness."
• Na⁺, K⁺ – related to "saltiness" and conductivity; in softeners Na⁺replaces Ca²⁺/Mg²⁺.
• HCO₃⁻ – buffers pH (stabilizes taste, reduces corrosion).
• Cl⁻, SO₄²⁻ – at higher concentrations can worsen taste.

Electrolytes and conductivity and TDS

TDS (mg/l) is an estimated sum of dissolved substances; in home practice, it is calculated from conductivity (EC, µS/cm). HighTDS means more ions, but it doesn't specify "which" – a detailed ion profile from water testing is needed for accurate assessment.

It's worth remembering: WHO links taste acceptability with TDS: <300 mg/l – "very good", 300–600 mg/l – "good"; beyond that, the taste becomes noticeably worse. High TDS is mainly an aesthetic issue, not a medical one.

Water mineralization: label interpretation

On the labels of bottled waters, you will find the total mineral content (mg/l) and specified ions (Ca, Mg, Na, HCO₃, etc.). In the EU and Poland, accepted mineralization thresholds are used, which are helpful for quick selection.

Thresholds: very low, low, medium, high mineralization

• Verylow-mineralized – ≤ 50 mg/l
• Low-mineralized – < 500 mg/l
• Medium-mineralized – 500–1500 mg/l
• High-mineralized – > 1500 mg/l

Worth remembering: “Low-mineralized” (<500 mg/l) is neutral in taste and versatile. "High mineral content" (>1500 mg/l) has a distinct taste and higher TDS – it will be appreciated by some athletes and lovers of "substantial" water.

Sodium and the designation "suitable for a low-sodium diet"

Waters with Na < 20 mg/l can be labeled as suitable for a low-sodium diet. When Na > 200 mg/l, the label indicates that it is "water"soda". If you are monitoring sodium in your diet, check this parameter first.

Taste and drinking comfort vs TDS and anions

Taste perception is a combination of TDS and ionic composition. The WHO indicates that water with TDS up to about 300 mg/l is usually perceived as very tasty. In contrast, high levels of chlorides and sulfates can give a sensation of saltiness or "bitterness".

• Chlorides ~200–300 mg/l often spoiltaste.
• Bicarbonates (HCO₃⁻) stabilize pH and "round out" the taste.
• Very low TDS can be perceived as "flat".

Key thought: TDS is aesthetics and taste. It is not "health quality." For health, compliance with microbiological and chemical standards and the stability of the installation matter.

Impact

Different technologies affect minerals in water differently. The choice should be based on water analysis, purpose (taste, appliance protection, barista), and operating budget.

Reverse osmosis (RO) and remineralizer

The RO membrane removes most ions (decrease in TDS and conductivity). For taste and pH stability, a remineralizer (e.g., a cartridge with calcite ordolomite), which doses Ca/Mg ions and slightly raises the pH. This is also standard in desalinating seawater – to limit corrosion and obtain "stable" water.

Ion exchange softener vs sodium/potassium

The softener (cation exchange resin) exchanges Ca²⁺/Mg²⁺ for Na⁺ (or K⁺, when using potassium salt). The amount of sodium after softening depends on the initial hardness and the settings of the device. Watersoftened water is safe, but if you need to medically restrict sodium, consider: KCl salt for regeneration, a separate tap with untreated/RO water for drinking, or RO after the softener.

Ultrafiltration and activated carbon

UF (membranes with pores of ~0.01 µm) and carbon filters improve clarity, taste, and odor, usually without significant change in mineralization. This is a good choice when you want to maintain the natural mineral profile, andsimultaneously filter out particles, color, and chlorine.

It's worth remembering: RO – deep purification and low TDS, usually with a mineralizer. Water softener – less scale, higher Na⁺/K⁺. UF/carbon – better taste and clarity while retaining minerals.

What water and filter to choose forYour needs?

A few practical scenarios – regarding taste, appliances, and drinking habits:

• For "delicate" taste: low or very low mineralized water (TDS ~100–300 mg/l). RO + mineralizer set to "gentle".
• For espresso machines/baristas: moderate HCO₃⁻ and Ca/Mg (protection against scale and extraction balance).Often: RO with a mixing/variable mineralizer.
• When limescale damages appliances: a softener for the whole house (for laundry/bathroom), and for drinking – RO with a mineralizer or an under-sink UF line.
• After exertion and heat: choose water with clear Ca/Mg and sodium or add electrolytes in a sachet. These are nutritional tips – they do not replace medical advice.

Recommended product: WODARO FLOWLINE – compact under-sink filter (UF 0.01 µm, calcium sulfite beads, activated carbon, KDF). Retains minerals, improves taste and clarity. For kitchens where easy installation and no tank are important.

Quick indicators and measurements at home

Simple measurements allow you to control taste and servicefilters.

TDS/conductivity meter – what does it show, and what does it not?

• Shows: an approximate sum of ions (electrolytes) in mg/l (from EC).
• Does not show: which ions are more/less or microbiology. For that, a laboratory test is needed.
• WHO: very goodTaste acceptability is usually at TDS < 300 mg/l.

Water hardness – the most important conversions

• Classification (USGS): 0–60 mg CaCO₃/l – soft, 61–120 – moderately hard, 121–180 – hard, >180 – very hard.
• Conversion: 1 °dH ≈ 17.8 mg CaCO₃/l (useful when setting up a water softener).

Summary

Electrolytes in water are a practice, not a theory: they determine taste, scale, and conductivity. First assess the intention (taste/appliances/espresso/rehydration), then choose the technology (UF, RO with mineralizer, softener) and parameters.

Key thought: "Better" water is one that meets standards, tastes good to yourfor the family and is matched to the appliances. The rest are conscious settings and service.

Frequently Asked Questions (FAQ)

Does TDS indicate if the water is "healthy"?

No. TDS is an aesthetic/taste indicator. Safety is determined by compliance with microbiological and chemical parameters according to applicable regulations.

Is it worth "raising TDS" to make the water "richer"?

There is no general requirement for minimum Ca/Mg content in drinking water. Higher TDS may improve taste for some people, but it's a preference – not a health standard.

How much sodium does a water softener add?

It depends on the hardness and settings. The softener exchanges Ca/Mg for Na (or K). If you're limiting sodium, consider KCl salt or a separate source of drinking water.(np. RO).

RO "washes out minerals" – is this a problem?

RO lowers TDS, but with a mineralizer, it's easy to restore the desired taste/pH profile. Sources of minerals in the diet are mainly food, not water.

What water should you choose for coffee?

Moderate hardness and HCO₃⁻ buffer provide a stable taste and less scale. Practically: RO with blending or a mineralizer set to the profile.barista.

Does water "for a low-sodium diet" have formal criteria?

Yes – it can be declared on the label at Less than 20 mg/l.

Why does very low TDS sometimes taste "flat"?

It lacks ions that provide "fullness." A simple mineralizer with calcite/dolomite often resolves the issue.

Does high TDS harmDevices?

High Ca/Mg creates scale. A whole house softener protects installations; for drinking/espresso choose RO/UF according to taste preferences.

Is conductivity (EC) the same as TDS?

TDS is calculated from EC (coefficient ~0.5–0.7), but this is an estimate. The exact composition requires testing.

Is plain water enough after intense exercise?

In case of significant sweat loss, it is advisable to replenish electrolytes (Na, K, sometimes Mg). This is a nutritional tip; if in doubt, consult a specialist.