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How to Test for the Hardness of Water

The most common water problem is hardness, which is caused by calcium. No natural water supply is free of hardness. Hardness is measured in grains per gallon, parts per million or milligrams per liter. If you are testing swimming pool water, most swimming pool stores will test your water for free if you bring in a sample. However, you can test your water for hardness at your home or in your pool using a water hardness test kit.

How to Test for Water Hardness

Purchase a water hardness test kit at your local hardware or swimming pool store. Inside are two vials filled with liquid, one labeled GH (for general hardness) and the other KH (carbonate hardness). There also will be two empty tubes within the kit.

To test your home's water, fill the empty tube with tap water. Fill it only to the “test” line. Put two to three drops of the GH liquid into the water. Allow the drops to settle and view the results. The test tube is designed to show you if the GH level in your water is too high or low.

Take the other empty tube and fill it with tap water. Repeat step two using the KH liquid. Check the results to determine if the KH is too high or low.

Once you have determined whether or not your water is hard, you can decide what action to take if necessary, such as buying a water softener to remove hardness.

Reduce Pool Water Hardness & Alkalinity

Don't let all the technical terms and details overwhelm you - in simple terms, your swimming pool must maintain a stable chlorine level and stay balanced. Balance refers to three component levels: pH, total alkalinity (TA) and hardness. If your chlorine level is too low, you add more chlorine. Related to pH, total alkalinity is a measure of the alkaline substances in the water. Dip a test strip about 18 inches below the water surface, following the manufacturer's instructions, then remove. Compare the test result color against the test kit guide to determine the TA level. Measure your choice of TA-lowering chemical, either sodium bisulfate or muriatic acid. Lay across the pool deck or bend over an aboveground pool to position yourself close to, but not touching, the water. Test the pool water for hardness. Compare the results to ideal levels of between about 200 and 400 ppm. Drain a portion of the pool water to adjust the water hardness. Softened water, such as tap water treated by a water softener, will lower the hardness. Commercially purchased pool water is already treated and balanced, giving you a head start on conquering your pool chemistry problems, and is as easy as running the truck's hose to your pool. Borax is preferable as soda ash tends to raise the TA and pH. Test the hardness level again after seven days. During this period, the minerals bind with the chemicals to form larger molecules, which are then flushed out of the pool through the filtration system.

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