Why is our limestone coping on saltwater pool turning white?

Limestone coping on a saltwater pool turning white is a common issue caused by calcium buildup. Saltwater pools generate chlorine through a process called electrolysis, which can increase the pH levels of the pool water. High pH levels cause calcium to precipitate out of the water and form a scale on the coping. Here are a few reasons why your limestone coping may be turning white:

High pH levels: Saltwater pools tend to have higher pH levels than chlorine pools, and this can cause the calcium in the water to precipitate out of solution and form a scale on the coping.

Calcium Hardness: The calcium hardness of your pool water is another factor that can affect the formation of calcium scale. If the calcium hardness is too high, it can contribute to the buildup of scale on the coping.

Evaporation: In saltwater pools, the evaporation of water can leave behind dissolved minerals on the coping, further contributing to the white buildup.

Type of Limestone: Certain types of limestone, such as softer varieties, may be more prone to calcium buildup compared to denser varieties.

To prevent or remove white calcium buildup from limestone coping, here are a few tips:

1. Regular Maintenance: Regularly brush the coping to remove any calcium deposits that may be forming.

2. pH Control: Keep the pH levels of the pool water within the ideal range of 7.2 to 7.8 to minimize calcium precipitation.

3. Control Calcium Hardness: Maintain the calcium hardness of the pool water within the recommended range specified by your pool equipment manufacturer.

4. Acid Washing: If the calcium buildup is severe, you can clean the coping with a diluted hydrochloric acid solution (muriatic acid) following the manufacturer's instructions and safety precautions.

5. Sealing: Applying a sealant specifically designed for natural stones can help protect the coping from calcium buildup.

6. Coping Replacement: If the limestone coping is severely damaged due to calcium buildup, replacing it with a more resistant material may be necessary.

Remember to consult with a pool maintenance professional for specific recommendations and guidance tailored to your pool conditions to prevent or address white calcium buildup on your limestone coping effectively.