A guide to cleaning swimming pool water with clorine or bromine treatments.
By Don Vandervort, HomeTips
Water—and especially heated water—is a breeding ground for algae and other micro-organisms that carry disease. For this reason, sanitizing your pool water on a regular basis is essential to pool maintenance.
Chlorine Treatments for Pools
The traditional method of sanitization is the use of chlorine, which not only eliminates bacteria but is also able to break down organic debris through oxidation.
Chlorine comes in liquid form, though this is not commonly used for home pools; granular form, which is dissolved before being added to pool water; and tablet form, which is placed in a floating feeder that slowly dissolves and then releases the chlorine into the pool. The chlorine, in reaction with the pool water, produces hypochlorous acid, or what is called “free chlorine,” which is actually what sanitizes the water. But, free chlorine degrades rapidly in sunlight, so cyanuric acid, which stabilizes the compound, is added with the chlorine.
After treating your pool water with chlorine, you will have to check its level regularly to see if you need to add more. Test kits are readily available at pool-supply stores. (A kit that also measures pH and calcium levels, plus alkalinity, is recommended.) Your free chlorine level should be 1–2 parts per million (ppm). The amount of chlorine you may need to add depends greatly on your pool use; expect to add chlorine daily during the heavy-use summer months.
Always follow label directions to the letter, and never mix more than one type of brand. Chlorine compounds can be corrosive, to your pool and to you. As you will have to handle the chemical by hand, make sure to wear proper protection on your hands and face.
If you are using the granular form, mix it by adding it to water and not the other way around to ensure it does not splash on you. Pour the solution into the pool in several different places, as close to the surface as you can. The tablet form is simply added to the feeder.
Chlorine Shock Treatment for Pools
A chlorinated pool typically contains two types of chlorine. Free available chlorine (FAC) has maintained its pure chemical composition and is standing at the ready to clean up contaminants. Combined available chlorine (CAC), also called chloramine, has already done its work and now is impure because it has combined with ammonias and other contaminants in the water. (These contaminants, for the most part, come from urine, sweat, and saliva.)
When a pool smells like it has too much chlorine and the water burns your eyes, you are actually smelling the contaminated CAC rather than the pure FAC. We often think that the odor and irritation are the result of too much chlorine, but they actually indicate that there is not enough FAC in the water.
The solution is to “shock” the water by adding a large dose of chlorine, a process called super-chlorinization. This megadose breaks down the CAC and re-establishes a healthy level of FAC.
Optimally, you should administer a chlorine shock at night, after people have finished swimming, so the water can have time to recover. At the very least, give it an hour or so before allowing people into the pool, and make sure the pump and filter are operating. Purchase an amount of shocker suitable for your size pool. One form is a powder that you scatter over the water at various locations in the pool. Use a free-chlorine test kit to make sure you have achieved free chlorinization. If the treatment did not work sufficiently, repeat it.
If a pool is heavily used, you may need to shock it on a weekly basis. Otherwise, administer a shock when the pool smells bad or when a test kit reveals the need. If you want to lessen your maintenance time by partially automating the task, consider installing a salt chlorine generator (see Swimming Pool Sanitization: Salt Chlorine Generators). Bromine Treatment for Pools
Bromine, which is commonly available in tablets the same way chlorine is, has some advantages over chlorine. While chlorine combines with contaminants to produce combined available chlorine, which is foul smelling and irritating to eyes and skin, bromine produces bromamines, which are odorless and non-irritating.
With bromine, you do not need to apply periodic shock treatments as you do with chlorine. And bromine works quickly, so swimmers can jump in the pool soon after treatment.
However, there are some drawbacks. Bromine breaks down in sunlight, so pure bromine is not very effective for outdoor pools that are shaded. For that reason, many bromine tablets contain a significant amount of chlorine to help stabilize them. And bromine is more expensive than chlorine.
For these reasons, bromine is more commonly used for indoor pools and spas than for outdoor pools.
