Ten Minutes a Week is all it Takes to
Keep Your Swimming Pool Water Clean
with a Test Kit
To the new pool owner, terminology like pH, calcium hardness, total alkalinity (TA) and chlorine residual might suggest the need for a degree in chemistry to maintain the water in a pool. Nothing could be further from the truth. An adequate test kit and a visit to your local swimming pool and spa care professional will provide you with enough basic knowledge to keep the pool water clean and sparkling all year round.
You may think that if a swimming pool contained absolutely pure water such as the distilled water used in a car battery, pool chemical treatment would be easier. However, this is not so, as water needs a level of dissolved minerals to act as anchor for its chemical balance. In order to make pool maintenance easier and to lengthen the life-span of your pool surface and the equipment, every pool owner should take a water sample to a reputable pool and spa care professional for complete analysis to establish pool water balance. Regular water testing is recommended to maintain ideal water balance.
Pool owners need only carry out two simple tests on a weekly basis during summer: free chlorine residual and the pH level. But if your test kit is more than six months old and you are using liquid testing reagents, throw them away and replace them from your local pool shop.
Pool Water pH Level
The pH scale runs from 0 (zero), which is acid in its most concentrated form, to 14, which is alkali in its most concentrated form. Half way along the scale, at 7, a material is considered to have a neutral pH. This means it is neither alkaline nor acidic. The ideal pH of pool water is 7.4 – 7.6.
The pH is also affected by impurities that fall into the pool – leaves, dust, atmospheric pollution, urine, cosmetics, perspiration – and as these all have their own pH level, will naturally affect the pool. For chlorine to work most effectively, and to ensure a level of bather comfort, it is necessary to continually adjust the pH to the recommended levels.
If the pH is too low, the pool will need additional alkaline material. The pH can be easily raised with the addition of dry alkali. If the pH factor is shown to be too high it can be lowered with the addition of acid (dry or liquid). Dry acid is preferred as it is safer to handle, store and transport.
Note that irrespective of how high the pH is in a pool, it is not recommended that large doses (more than one cupful of acid) be added to the pool at any one time.
Chlorine Level in Your Pool
The addition of chlorine to swimming pool water is still the most commonly recommended means of controlling bacterial growth and algae. There are currently several ways of achieving this, including the use of granular chlorine, tablets, floaters and salt-water chlorination.
When chlorine (in whatever form it is chosen) is added to a swimming pool, it forms hypochlorous acid, which is an oxidizer. This literally burns up and destroys impurities in the water by breaking up their molecular structure. For the chlorine to work most effectively it is necessary for the pH level to be within the recommended limits.
Since chlorine is destroyed both by ultra violet rays from the sun, and by doing its job of killing algae and bacteria, it is used up quite quickly, particularly in the hot, summer months. This means that during the swimming season it will be necessary to add chlorine regularly in order to maintain a sufficient level of 1–3 parts per million (ppm).
Value of Using a Test Kit
Using a test kit makes it simple to ascertain the chlorine level in a pool at any time. However, it must be understood that the amount of chlorine needed to maintain a safe level will vary considerably. Naturally the temperature of the water, and its bathing load, will affect the chlorine needs. For example, a pool which is used extensively by many children on a summer’s day will require far more chlorine than it will standing unused during winter. It is therefore necessary to check the chlorine level of a pool daily in order to ascertain the amount required to keep it a safe level.
Since the ultra-violet rays of the sun destroy chlorine, stabilised chlorines should be added. These maintain more consistent chlorine residuals in a pool and reduce the need to keep adding chlorine.
Over time, swimming pool water accumulates a build-up of waste material that eventually turns water cloudy and dull and becomes irritating to the bathers who come in contact with it. People as well as animals, insects, pollutants and the general environment introduce these wastes, which are not capable of being filtered out. These wastes not only cause dull, cloudy water which is irritating, but it also becomes resistant to algae.
Ensure that the filter is back-washed weekly and that the leaf basket in the weir and the pump are clear of rubbish. When the filter is switched on, a strong current of water should be flowing into the weir and returning to the pool at the return points. If this is not the case, contact a pool service company for advice.