Why Water Hardness Is So Important for Your Pool
The following is general advice only. Requirements for individual pools and pool systems may vary.
When it comes to keeping your pool in pristine condition, most pool owners are familiar with balancing pH and chlorine levels. However, one essential factor that's often overlooked is water hardness. Understanding and maintaining proper calcium hardness levels in your pool is critical to the health of your pool water, surfaces, and equipment.
What Is Water Hardness?
Water hardness refers to the concentration of dissolved calcium and magnesium minerals in your pool water. In pool care, the focus is primarily on calcium hardness, as it's the mineral that has the most significant impact on your pool's condition.
Water can be classified as:
Soft: Low calcium levels
Hard: High calcium levels
The ideal calcium hardness level for most pools is between 200–400 ppm (parts per million), although specific needs may vary depending on pool type and location.
Why Does Calcium Hardness Matter?
1. Protects Pool Surfaces
If calcium levels are too low, the water becomes "hungry" and will begin to draw calcium from wherever it can — usually from your pool's plaster, tile grout, or concrete surfaces. This causes etching, pitting, and surface degradation over time.
On the other hand, high calcium hardness can lead to scaling, where calcium deposits form on the pool walls, floors, and waterline tiles. This not only looks unsightly but also makes cleaning more difficult.
2. Preserves Pool Equipment
Low calcium levels can corrode metal components such as ladders, heaters, and pumps. Conversely, high calcium levels can clog pipes, filters, and heat exchangers with scale buildup, leading to reduced efficiency and costly repairs.
3. Maintains Water Clarity and Balance
Improper hardness levels can destabilize your pool's water chemistry, making it harder to maintain proper pH and alkalinity. This imbalance can cause cloudy water, algae growth, and increased demand for sanitizers like chlorine.
How to Test and Adjust Calcium Hardness
To keep your pool water balanced:
Test regularly using a reliable pool test kit or bring a sample to your local pool store.
If calcium hardness is too low, add a calcium increaser (calcium chloride).
If calcium hardness is too high, you may need to partially drain and refill the pool with softer water or use specialized treatments.
Final Thoughts
Water hardness might not be the first thing that comes to mind when you think of pool care, but it plays a vital role in protecting your investment. By maintaining the correct calcium hardness level, you’ll ensure your pool water stays clear, your surfaces remain intact, and your equipment runs efficiently for years to come.
Need help with testing or balancing your pool water? WaterPro Pool and Spa offers professional water testing, expert advice, and the right products to keep your pool safe, clean, and enjoyable all season long. Our services include inhouse water testing, home visits if you prefer DIY, and a variety of pool services. Contact us here or on 1300 447 665 for more information.