1. What is Total Hardness of Water?

Definition: The Total Hardness of Water formula is defined as the sum of the calcium and magnesium concentrations, both expressed as calcium carbonate.

Purpose: It measures the concentration of dissolved calcium and magnesium in water, which affects water quality and suitability for various uses.

2. How Does the Calculator Work?

The calculator uses the formula:

Where:

• \( TH \) — Total Hardness of Water (mol/m³)
• \( Ca \) — Calcium Concentration (mol/m³)
• \( Mg \) — Magnesium Concentration (mol/m³)

Explanation: The formula calculates the combined effect of calcium and magnesium ions in water, which are the primary contributors to water hardness.

3. Importance of Water Hardness Measurement

Details: Water hardness affects soap efficiency, scale formation in pipes and appliances, and can impact industrial processes and drinking water quality.

4. Using the Calculator

Tips: Enter the calcium and magnesium concentrations in mol/m³. Both values must be ≥ 0.

5. Frequently Asked Questions (FAQ)

Q1: Why are calcium and magnesium the main contributors to hardness?
A: These divalent cations form insoluble salts with soap and cause scale formation, which are the primary characteristics of hard water.

Q2: What are typical hardness values for drinking water?
A: Soft water has less than 60 mg/L CaCO₃, moderately hard 60-120 mg/L, hard 120-180 mg/L, and very hard over 180 mg/L.

Q3: How can I convert mol/m³ to mg/L CaCO₃?
A: Multiply mol/m³ by 100.09 (molar mass of CaCO₃) to get mg/L as CaCO₃ equivalent.

Q4: Does this include other hardness-causing ions?
A: The standard definition focuses on Ca²⁺ and Mg²⁺, though other divalent cations can contribute minimally.

Q5: How does water hardness affect industrial processes?
A: Hard water can cause scaling in boilers and cooling systems, reduce soap efficiency, and interfere with some chemical processes.