Swimming pools could be classed as “communal baths” and the water in them is subject to contamination by such things as nasal discharges, urine, feces, perspiration, hair and general debris carried in on bathers’ feet or blown in by the wind.
Unless the water is treated satisfactorily it will provide an excellent media for the growth of bacteria, fungi, algae and other forms of organisms. If allowed to multiply in the water these organisms will spread disease.
The water in a pool should be:
- Sparkling clear to look at. A 20c coin should be recognized as heads or tails in 1.5 m of water.
- Correctly treated chemically to ensure adequate disinfection and not a health hazard to bathers.
To achieve this, you will need filtration and disinfection.
Whatever filter a pool has it can only be as effective as the maintenance given it and how it is operated. Read the manufacturer’s instructions as to the frequency of backwashing, etc. As a general rule, however, filters should be operated 24 hours a day during the swimming season.
Smaller, above-ground pools can run the filter intermittently, depending on the loading on the pool. An electric motor can be annoying to neighbors, so ensure that the motor and filter are adequately soundproofed.
Disinfection must be carried out to destroy any pathogenic microbes in the water and the most common material used for disinfection is chlorine.
When chlorine is added to water it forms into two acids, and it is these acids that destroy any microbes. The more acidic the water the better the sanitizing effect will be, however as an “acid-water” will affect bathers, it is necessary to rationalize the effect.
Acidity and alkalinity are measured on a pH scale. Distilled water is neutral at pH7 and the scale ranges from 0-14. 0-7 is acidic, 7-14 is alkaline, the further away from 7 the more acidic or alkaline the water is.
Chlorine has to oxidize the organic matter (i.e. body discharges and general debris) in the pool and in so doing it combines with other chemicals. The most common and the most bothersome combination is chlorine and ammonia combined to form chloramines. It is these chloramines that give rise to eye irritations.
The method of chlorination used today is called “breakpoint” chlorination. The breakpoint is achieved when chlorine is added until no more is taken up by the organic matter and the chlorine left is “free chlorine” (i.e. free to disinfect).
This chlorine is available to destroy any organic matter (including microbes) enter ing the pool and is known as “free available chlorine” (FAC). The true breakpoint is when the readings of total chlorine and FAC are the same.
Various testing kits are supplied by pool manufacturers and suppliers. Most kits are very basic, but they do enable tests to be made for FAC and pH. Some will test for total alkalinity as well.
Test the pool twice each day, in the evening when adjustments to the water quality can be made and in the morning before the pool is used. Adding any chemicals needed in the evening enables the pool to stabilize overnight.
- Visit the lavatory before entering the water.
- Shower BEFORE entering the pool.
- Don’t let people with open sores, bad coughs, or sore throats use the pool.
- Minimize grass, soil, and other debris being tracked into the pool.
- Use a pool cover when the pool is not in use. This minimizes the loss of chlorine.
Pool chemicals are hazardous; chlorine powder will ignite spontaneously if contaminated with oil, grease, or if it becomes damp.
Swimming pool testing re-agents are often poisonous. Keep them out of reach of children.