How long do you superchlorinate a pool?

Answer 1

Shock Treating/ Super Chlorinating "Burning up the pollutants with strong oxidizing chemicals" Shock treating or shocking refers to the addition of anything to the water that will remove or destroy ammonia and nitrogen compounds by oxidation - traditionally this has been chlorine. There are now some non-chlorine shock products. Organic matter and ammonia compounds enter a swimming pool or spa from many sources. Swimmers and bathers are major contributors with their bodies giving off saliva, sweat, urine and faecal matter. Windblown dust, fertilisers, algae, leaves, twigs, certain water-treatment chemicals and rain introduce contaminants into the water. Chlorine and bromine combine with ammonia and nitrogen compounds to form amines. Chloramines smell bad, they are eye and body irritants and they are also poor disinfectants. Bromamines do not have an odour problem and are as effective as free bromine for disinfection. Organic wastes build up and become sources of irritation. Dealing with the problem of combined chlorine requires testing the water to see how much of the chlorine in the water is free and how much is combined. The commonly used OTO test will not perform this task. It can only tell you the total chlorine level and can't differentiate between free and combined chlorine. However, a DPD test kit or a syringaldazine test strip will do the job. When chlorine is introduced into swimming pool or spa water it forms hypochlorous acid (HOCl (free chlorine)) which dissociates into H+ and OCl-, the degree of dissociation depends upon the pH. The OCl- is a strong oxidiser and will oxidise the ammonia to form a combined chlorine compound known as monochloramine (NH2Cl) and OH-. More chlorine as OCl- is required to continue the oxidation of the nitrogen or ammonia. If no more chlorine was in the pool or added to it, the pool or spa water would have a large amount of combined chlorine as monochloramine rather than the desired free chlorine. As more chlorine is added, the monochloramine is now oxidised by the additional chlorine as OCl- to form dichloramine (NHCl2 + another OH-). The dichloramine is again oxidised by OCl- to form trichloramine (NCl3 + another OH-). The trichloramine is unstable and breaks down to simple nitrogen and chlorine completing breakpoint chlorination. Superchlorination to truly achieve the destruction of all organic waste can be very tricky. If not enough chlorine is added, the combined chlorine problem is only made worse. When this happens, eye burn and skin irritation are raised to very high and very irritating levels. If too much chlorine is added, it may take days to drop to safe levels (less than 5 ppM) before bathing can be resumed. It takes 7.6 parts by weight of chlorine to oxidise 1 part of ammonia. Other organics or products in the water will also consume some of the added chlorine so that 7.6 parts is not enough. 10 parts of chlorine for each part of ammonia is generally the required amount. Dirty and contaminated pools could take up to 25 parts or more of chlorine. As a general rule of thumb, the addition of 10 times the combined chlorine level will achieve breakpoint. In other words, if the water has 0.5ppm of combined chlorine by test, you will need to add 5 ppM or more of chlorine. Each of the popular chlorine products provide a different amount of available chlorine when added to water. In a typical 100,000 litre pool it will take about 1 kg of available chlorine to achieve 10 parts per million.

Answer 2

Only if there is a problem that normal chlorine levels cant handle.