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When you shock your pool you use the process of oxidation to chemically remove (burn up)
organic debris, such as body waste, particulate matter and perspiration, from the water. All
pools require a shock treatment on a regular basis to maintain optimum water quality.
Routinely shocking the water following your chemical program¡¯s recommendations will greatly
increase the water quality of your pool. In addition to oxidizing undesired wastes ¨C shocking
will help rid the pool of algae and bacteria that might be hiding in filters and hard-to-sanitize
Contrary to what most people think, a strong chlorine smell is not an indication of too much
chlorine in the pool but actually a red flag that a super dose may be required to correct the
problem. A properly balanced and chlorinated pool will have no discernible odor. In chlorine
treated pools shocking can be achieved by superchlorination (adding a much higher chlorine
amount than normal). Hypochlorous acid is the form of chlorine that provides sanitization.
Hypochlorous acid is very active and will react with ammonia and other nitrogen-containing
organic compounds (i.e., perspiration, urine, etc.) and form chloramines. This ¡°combined
chlorine¡± is 40 to 60 times less effective than free available chlorine. Combined chlorine, in
addition to reduced effectiveness against bacteria can cause eye irritation and so called
¡°chlorine odor.¡±
The following are GENERAL recommendations for shocking your pool water. For more
complete instructions follow your specific chemical program instructions, shown below.
Every 2 Weeks*:
When the temperatures are 80¡ã F or below
When the temperatures are above 80¡ã F
Heavy bather load (after the pool party!)
As Needed:
At the first signs of visible algae (slippery walls or floor)
Cloudy water (check water balance as well)
Heavy rains or storms (increase organic debris in water)
Most biguanide programs require a monthly shock treatment using the specific shock in your program.
As mentioned above, the sanitizer program you use to treat your pool will determine the type of
shock you can use. Not all shocks are compatible with all sanitizers, so be sure to follow the
recommended shock treatment for your treatment program, shown in the link at the bottom of
this page. The chemicals used for shock treatments are powerful oxidizers. CAREFULLY
read and follow the recommendations in the Chemical Safety-oxidizers section.
It is most effective to shock in the evening as chlorine shock dissipates very rapidly in
If you are using a chlorine shock treatment you will have a very high chlorine reading (10
ppm or higher). You must allow the Free Chlorine level to drop back down to the safe range
of 3 ppm or lower before re-entering the pool. This can take up to 24 hours, so plan
according when superchlorinating or use a non-chlorine shock (mono-persulfate) if the pool
will be in use sooner. Non-chlorine shocks and biguanide shock treatments allow you to re-enter
the pool within 15 to 30 minutes after treatment.
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