Effects of Calcium Hardness Levels on Swimming Pools

After pH and total alkalinity, the calcium hardness of your pool is another very important aspect of pool water quality. Calcium hardness is not just a fancy term used by pool professionals. It is a critical aspect that every pool owner should be aware of and monitor regularly to prevent potential problems. It is a basic test for water balance. The minimum allowable value of calcium hardness is 150 mg/L. The ideal range is 180–250 mg/L (plastic liner pool) or 200–275 mg/L (concrete pool).

Calcium can also be interpreted as the “softness” or “hardness” of the water. If your pool has high calcium hardness, it is considered “hard water”. On the other hand, if the calcium hardness is low, the pool water is called “soft water”. Calcium content is equally important for your pool and spa, and it provides protection for the structural health of the pool itself.

Sources of Calcium in Pool Water

Source water being too soft or too hard is the main factor. If your pool disinfectant is calcium hypochlorite, it will also be one of the sources of calcium in your pool. If the water is too soft, The calcium in your pool can be found in the pool walls or pool bottom tiles, and it can also come from your raw water.

If the Calcium Hardness of your pool is imbalanced, you may be dealing with wall corrosion, cloudy water, and of course, calcium deposits.

Effects of Calcium Hardness Variations in Pools

Calcium Hardness Too High

When the calcium content in pool water is too high, the water will start to look a bit cloudy. This is because the water becomes saturated, causing the calcium to precipitate out. It causes scaling, where masonry and tiles soaked in water will begin to take on a scaly white color due to calcium deposits. . This process involves calcium coating and sticking to everything that comes in contact with it in the pool water. Scaling can also seriously affect the heat transfer efficiency of heaters, cause clogging of pipes and filters. Increased electricity costs.

Calcium Hardness Too Low

When the calcium content is low, the water gradually becomes corrosive. In this case, the water will corrode when it comes in contact with the plaster, concrete or tiles in the pool, and the pool water will easily bubble. In the long run, this can damage the pool’s masonry due to etching, causing scars and blemishes.

How to Reduce Calcium Hardness in Your Pool

You can reduce calcium hardness in your pool water by one or more methods, including:

1. Freshwater dilution: Drain part of the pool and then fill it with clean water that has lower calcium hardness

2. Add metal chelators

How to Increase Calcium Hardness in Your Pool

To increase calcium hardness in your pool water, you can add calcium chloride to it. However, you must be careful when adding calcium chloride. Adding too much calcium chloride can significantly increase the calcium content, which is something you don’t want to see. So follow the supplier’s operating instructions for adding it.

Whichever method you use to solve the calcium hardness problem, you will eventually need to adjust all indicators to normal ranges

Daily Maintenance

Regular Testing: Use a pool water quality testing tool or seek professional pool service to test calcium hardness levels monthly. This will help you monitor calcium hardness and make necessary adjustments.

Regular Maintenance: Clean and maintain your pool to prevent scaling and other problems associated with high calcium hardness. This includes scrubbing the pool walls, cleaning the filter, and ensuring proper circulation.

Balance of any chemical indicator in your pool is critical. For any questions and chemical needs, please contact “YUNCANG”.