How to Test Calcium Hardness in a Swimming Pool

Calcium hardness measures the mixture of all the chemicals in your pool, including sodium and magnesium. The level for calcium hardness is 200-400 ppm. If you go lower than this level, your pool gets corrosive and the water becomes cloudy. If you have too high a calcium level, your pool gets scales or calcium deposits. The following steps will help you test calcium hardness in your pool.

Difficulty: Moderately Easy

Instructions

1. Recognize that your pool water is cloudy or the pool surface has scaling. Swimmers in your pool may also complain of their eyes getting irritated.

2. Purchase calcium hardness test strips. Refer to the Resources section for a source of these supplies.

3. Dip one test strip into your pool water one time. Don't shake the water off after dipping.

4. Let the test strip sit for 15 seconds to dry a bit. Set it under the shade, not in a sunny spot.

5. Compare the color of your test strip to the color chart on the strip bottle by holding the two side by side.

6. Determine how you need to treat your pool to maintain your calcium levels. Review the Tips section for suggestions on how to treat your pool's calcium levels, if necessary.

Tips & Warnings

• Test your calcium levels weekly with the calcium hardness strips.
• If your levels are too low, add calcium chloride or any type of pool calcium increaser.
• If your levels are too high, reduce the water level. If the cause is increased water level, use a pool calcium hardness reducer.
• Too high a calcium hardness can irritate swimmers' eyes.

Resources

• Test strips
• Chart for calcium hardness vs. water levels