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Maintaining and Understanding Pool Water Chemistry

Courtesy In The Swim Discount Pool Supplies

Only two simple steps are required to properly maintain a swimming pool, and keep pool water safe for swimmers. These two important steps are circulation and sanitation. Circulation is easily achieved through the use of one of the many pool filter systems on the market today. Sanitizing swimming pool water and properly maintaining the pool water chemistry can be more difficult. Every swimming pool is a little different and there is no owner's manual with all of the answers to the many problems pool owners might run into. Armed with a basic understanding of pool chemistry and how pool chemicals work, any homeowner can maintain their own backyard swimming pool with the same results as the high priced professionals.

The most common method of sanitizing swimming pool water is through the use of the chemical chlorine. Chlorine is dissolved into your swimming pool water and combines with bacteria and other organics in the water on a molecular, level to kill these harmful contaminants. Once chlorine “combines” with the bacteria and organics in the swimming pool water, the chlorine becomes inactive and no longer work to sanitize your pool. The combined chlorine and organic contaminants are burned off by a weekly “shock treatment”, and removed from the water by the pool filter system.

Which type of chlorine should I use?

There seems to be many types of chlorine on the market, and each pool supply company works hard to make their chlorine product seem new and different. Chlorine is available in 3” tablets, 1” tablets, sticks and in a granular form. Upon inspecting the labels and comparing of all of the different brands of chlorine, you will see that the active ingredient is exactly the same in all of them. The active ingredient in 3” tablets, 1” tablets & sticks is called “Trichlor” (or Trichloro-S-Triazinetrione), and the active ingredient in granular chlorine is called “Dichlor” (or Sodium Dichloro-S-Triazinetrione). You will find a very wide range of prices for chlorine, and the only real difference you may find between the many brands of chlorine is the concentration of the active ingredients. You should look for a concentration of 99.5% Sodium Dichloro-S-Triazinetrione in granular chlorine, and a concentration of 99% Trichloro-S-Triazinetrione in chlorine tablets or sticks.

The type of chlorine you select depends upon your application, your preferences or your pool maintenance habits. The most common (and therefore the least expensive) form of chlorine is 3” tablets. 3” tablets are slow dissolving, which requires less maintenance. You can fill a floating chlorine feeder or automatic chlorine feeder with large amounts of slow dissolving 3” chlorine tablets, and if the feeder is adjusted properly, you may not have to worry about your chlorine level for a week or more. Water testing should always be performed at least two times per week to ensure proper water balance.

Another form of chlorine is chlorine sticks. Chlorine sticks are larger and dissolve even slower than 3” chlorine tablets, but are not as popular. 1” chlorine tablets dissolve more quickly than 3 inch chlorine tablets or chlorine sticks, and are better suited to above ground swimming pools, smaller in ground swimming pools or spas. Granular chlorine works just as well as the tablets and sticks mentioned above, however granular chlorine must be pre-dissolved in a bucket of water before adding to a swimming pool. Granular chlorine must be pre-dissolved and added to the swimming pool water almost every day. This allows very precise control over the chlorine level of the swimming pool, but requires daily testing and addition of the chemical.

Floating chlorine feeders and automatic chemical feeders are available from any pool supply distributor, to automatically dissolve 1 inch chlorine tablets, 3 inch chlorine tablets or chlorine sticks into your pool water. Automatic chlorine feeders are a great help to properly maintaining your swimming pool. Chemical feeders slowly meter out precise amounts of chlorine into your pool water automatically, and offer very precise control over the amount of chlorine being added to the swimming pool. You should never simply dump chlorine tablets or chlorine sticks into your swimming pool, or place chlorine tablets or chlorine sticks in the skimmer basket of your swimming pool. If a chlorine tablet is dissolving in your skimmer basket, all of the water passing through your pool plumbing and circulation system carries a high level of chlorine. This high concentration of chlorine slowly eats at the inside of the circulation system, and causes premature failure of your pool pump and pool filter components.

What is "Bromine"?  Sounds like heartburn medicine!

No, not quite silly girl!  Bromine is an alternative to chlorine used to sanitize swimming pools. The chemical bromine is very similar to pool chlorine in the way that bromine kills bacteria and harmful contaminants, but the two pool chemicals react in different ways. Bromine is most commonly used to sanitize spas/hot tubs because it is more stable than chlorine in the warmer spa water temperatures, and because of the lack of chemical odor in the water. The chemical bromine is preferred by many pool and spa owners because it causes less irritation of the skin and eyes. Because bromine is so stable, it can be harder to wash the chemical smell from your skin after bathing in a pool or spa that uses bromine. Bromine is available in tablet form and can be added to pool water using a chemical feeder to dissolve the tablets.

The difference between chlorine and bromine is that once chlorine combines with bacteria or harmful organics to kill them, most of the chlorine is used up and will no longer work to sanitize your swimming pool. This “combined chlorine” will be burned off by the next shock treatment and removed from the pool water by the filter. When bromine combines with bacteria in pool water, the bromine is still active but combined with the bacteria and organic matter to neutralize these harmful contaminants. When you shock a bromine pool the shock treatment only burns off the harmful contaminants, and leaves a good portion of the bromine behind in the pool water. The bromine left behind is available to sanitize the pool again. The result is that the volume of bromine tablets needed to sanitize a swimming pool is noticeably less than the volume of chlorine needed to do the same job.

There definite advantages and disadvantages to using bromine in a swimming pool. Bromine is considered better by some pool owners because bromine is usually much less irritating to the skin and eyes. Many pool owners with naturally sensitive skin prefer bromine.  However bromine is chlorine-based, and it will not help people who are allergic to chlorine. The disadvantage to bromine is that the chemical costs a good deal more per pound than chlorine.

Our thanks to In The Swim Discount Pool Supplies for this article.  Visit their site for all of your swimming pool and spa supply needs!

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