Calcium Hardness & Swimming Pool Water Chemistry

Have your swimming pool questions answered right here.

The ideal range for perfect swimming pool chemical maintenance of your pool is 150ppm-250ppm, not 250ppm-350ppm or higher.

This is especially true for saltwater pools and salt water pool system. If you add any more calcium hardness increaser your salt cells might calcify and burn up, shortening its life.

Swimming Pool Care

Water is hungry for calcium and will try to feed its appetite any way it can. Many times it will draw it from the plaster, which causes unsightly pitting, or from your filtration system, which will cause pool and chemistry problems.

Keep your calcium hardness level between 150ppm-250ppm will prevent this from happening. Some areas of the country may have very softwater or very hard water.

You don't need take your tap water anywhere and have expensive tests performed. Simply call your local water company and ask them the calcium hardness of the water supply for swimming pool, or use one of the many quality (Lamotte Test Kits) pool water test kits or pool test strips.

I prefer an FAS-DPD K-2006 Taylor Test Kit .

Here in central Oregon we have very soft water, about 1ppm-2ppm. In places like Arizona, Nevada, and Southern California the hardness may reach 200ppm-300ppm or higher.

Calcium Hypochloride Flakes

If you have a Hot Tub, spa, or heated pool, maintaining the proper calcium hardness in your water becomes even more critical. Most swimming pool problems result from bad pool chemistry advice given at the wrong time.

Take the time to understand the best pool tips for your swimming pool.

Problems With Low Calcium Hardness:

1. Pitting and etching of the plaster
2. Dissolved grout in your pool
3. Staining of the pool surface
4. Possible heater failure
5. Corrosive and scaling water
6. Supersaturation
7. Swimming pool stains

Problems With High Calcium Hardness:

1. Skin and eye irritation
2. Cloudy swimming pool water
3. Clogged pool filters
4. Poor filtration
5. Calcium build-up and corrosion on heaters
6. Scaling of the pool water

This is according to the Langelier Index that has been used for above ground pool maintenance, inground pool maintenance, and salt water pool maintenance for decades. Keep in mind, proper balance of your swimming pool chlorine, pool pH, pool alkalinity, and hardness is of the utmost importance in having a safe and clear pool water. It will decrease your chlorine demand, muriatic acid use, pool stabilizer, and alkalinity increaser.

What’s The Hardness Of Your Tap Water?

When you have softer water, you may need to add Calcium Chloride to feed your pool water’s appetite for calcium. DO NOT make slurry or mix the calcium chloride in a bucket with water. It may “steam” up and cause severe burns so there's no need to have a designated pool pole to stir anything.

Broadcast it directly into the pool, starting in the deep end and working around the perimeter of the pool. Apply the calcium as you would use a salt shaker. Refer to the chemistry help chart to see the amount calcium chloride your pool needs for your pool water care.

Any store that sells swimming pool equipment supplies or discount pool chemicals can help with your calcium needs.

Hard Water And High Calcium Fill Water

Having high calcium hardness (above 250-300ppm) in your tap water is very hard to keep down. Reducing calcium hardness is a bit more difficult. You may either replace some or all of your pool water or add chemicals, water softening or a Metal Sequestering Agent, that will reduce your water hardness. If your swimming pool problem persists consult your pool professional.

When filling your pool with fresh water, be sure to test the tap water for its hardness. This will give you a good starting point to see if you need to add calcium chloride or not.

Calcium Buildup In Pipes & Hard Water Scale Spots

Unfortunately there is no quick and easy answer on lowering the calcium hardness of your swimming pool water.

Remember what I said, it’s easier to add chemicals than it is to get rid of them. This is one such case.

When your fill water has elevated levels of minerals it can be troublesome to keep your pool’s calcium hardness at its proper level.

Chart - Raising Hardness With Calcium Chloride

Pool Water Testing For Calcium Hardness:

1. What is pool water hardness?
Water hardness is the makeup of the minerals (calcium, magnesium, iron, etc...) that are naturally found in tap and pool water.
2. When do I test for water hardness?
The best time to take any tests is in the late afternoon or early evening. Keep your pool’s hardness level between 150ppm-250ppm, not 350ppm or above.
3. Where do I test the water hardness?
The best place is either in the deep end of the pool or the furthest place from the filtration. Be sure to test you tap water as well so you’ll have the proper starting point with a freshly filled pool.
4. Why should I test for hardness?
Water hardness is one of the four elements that make up the test routine. Included in this are chlorine, pH, and alkalinity. Water is hungry for calcium and will take it from any source it can get. By keeping your water’s appetite for calcium fed and at the proper levels (if your fill water has low calcium hardness) you will minimize corrosive and scaling water, pitting of the plaster, clogged heaters and filters, and eye and skin irritation.

These pool tips will save you time, money, and maybe even a few migraine headaches.

Go swim and have fun with your family and friends.

Go To:

Swimming Pool Chemistry From Calcium Hardness
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Chlorine
pH
Alkalinity
Hardness
Cyanuric Acid
Sand, Cartridge, DE Filter

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