Calcium Hardness in Swimming Pools

Calcium hardness or CH for short, is the measure of the amount of dissolved calcium content present in your pool water. Calcium as we know it is a mineral that is naturally present in water and it is usually found in high concentrated levels. Whenever your pool or spa has high concentrations of calcium present, you have what is called hard water. On the other hand when the calcium level is low, you will have what we call soft water. to properly manage your pool water chemistry, you must remember that total hardness and calcium hardness in a spa or pool are different; although, they are related entities.

Total hardness is the sum of calcium, magnesium, iron, manganese, and other elements found in your water facility. It is usually expressed in grains of hardness (i.e. 1 grain = 17.1 ppm).The calcium hardness in swimming pools and spa water systems is ordinarily measured as calcium carbonate. However it is not in solution, calcium carbonate is exhibited in your pool and spa as scale. This is a white scale formation that is also a type of natural salt. This scale like salt can be found in nature in the form of one of the following

Chalk.
Calcite (check spelling).
Aragonite.
Limestone.
Calcium carbonate is not very soluble in water and unless your pool water chemistry is properly maintained, it can drop out of solution very easily. Another concerned behavior that pool owners and operators have with calcium, is that unlike most other pool chemicals, it becomes less soluble as the temperature goes up. Because of this basic understanding, proper management of hot water systems become more perplexed.
In order for you to maintain proper water chemistry in your swimming pools, your calcium hardness level should always be in the range of 200 to 400 ppm. If the level of the hardness in your calcium content rises above 400 ppm, you must take extreme measures to maintain your total alkalinity and pH at lower levels. This is a precaution that will help you avoid any scale formation in your pool and spa. This is an absolute must if the water in your aquatic facility is heated. You will be faced with an impossible task of maintaining your pool or spa water balance, if your Calcium level reaches 1000 ppm.

When your calcium hardness is too low!

Whenever the CH level in your swimming pool or spa is too low, the water in your facility will become very aggressive or very corrosive. Low levels of calcium is also a major contributor to foaming in spas or hot tubs. This is a pool water problem that is not good for the plaster or concrete surfaces in your pool or spa. The truth of the matter is that you should test the calcium content in your water regularly and if it is too low, take the necessary steps to correct it at once. Failure to take action, will result in your water having the capacity to leech or dissolve calcium carbonate from your pool and spa surfaces.

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