In this article I would like to review the various water treatment options available and to tell you what we at Aguaconcept Lda., consider to be the best for cleanliness, health and efficiency.
It is obviously important to keep pool water as free as possible from dust, sand, leaves, grease and hair - the basic job for which the sand filter and pump are designed, supplemented by a weekly vacuuming of the floor of the pool. Another basic protection tool is the pool cover, which will not only keep leaves and dust out of the water - and act as a safety net for children and animals - but will also reduce evaporation and raise water temperature (at Aguaconcept Lda., we prefer the type of cover that is suspended a few centimeters above the water, as it lasts longer, offers better thermal insulation and stays cleaner.)
Sand filter, pump, vacuum cleaner and cover are common to all modern pools. What is not common, and where the debate really begins, is the method of pool disinfection. No matter how good the filtration system, all pools will require disinfection to reduce the microbiological count of the water, as well as a method of maintaining the water's chemical balance. The smallest amount of dirt or leaves will serve as food for algae, fungus and bacteria, which will, if left untreated, produce dirty, green unhealthy water hardly an inducement to the swimmer.
The first, and most common method of disinfection, is the use of chlorine-based disinfectants, such as chlorine powder, chlorine pills or liquid chlorine (in portuguese: hipoclorito de sodio). These have a number of drawbacks. They form by-products chloramines from the reaction of the chlorine with the ammonia (or urea) shed by bathers, causing red eyes , skin irritation, the characteristic chlorinated pool smell , and not least, the ageing of fabrics found in and around the pool. Chloramines are also said to be carcinogenic.
Chlorine powder or pills also come with the addition of very nasty stabilizers and algicides, giving the impression that the chlorine is strong and long lasting. As well as being expensive, these products contain strong toxins such as mercury and other heavy metals, which not only contaminate the pool water but, through backwashing, the surrounding ground water too, and eventually the ocean. These toxins in turn accumulate in the seafood chain; tuna fish, for example, now contain high levels of mercury, mainly from pesticides and algicides. The consequences for human health include allergies, liver problems, cancer and a weakening of the immune system.
The second method of disinfection is the use of salt, added directly to the pool water, combined with an electrolytic cell. The salt in the water (sodium chloride) is partly converted to free chlorine and Sodium . Although the amount of salt in the water is at only 4000 to 8000ppm - much less salty than sea water which has 11.000 to 40.000ppm - it is still enough to make the water highly corrosive, which can destroy the iron structure of a pool quite quickly, especially if there are fissures in the concrete.
· It also substancially reduces the service life of pool heaters,
· while in hard water, electrolytical cells tend to clog and must be descaled frequently.
· The technology is rather simple and cheap and you can find units for an average pool size for less than 300 Euro . It is just an electroltytical cell (value : 30 Euro) and a simple controlbox ( value: 80 Euro) and some cables.
· The salt also is aggressive to natural stones around the pool and tends to damage the grouting in the pool
· Black algae is a very common problem in salt pools which frequently is solved by using very high levels of chlorine and algizide.
· The salt binds the chlorine in a way that you cannot smell or taste it , even if used in health threatening amounts.
· Each backwash of pool with average sizes flushes up to 8 kg of salt down the drain which is illegal saline pollution which can end up in our water supply. If the backwash water goes in your garden it can kill lots of plants and damage your soil. Over a period of ten years it can be tons of salt which are going down the drain or in your garden.
So although it may feel pleasant to swim in a salt pool, in the longer term it can produce a variety of expensive technical problems and even more important your health can be seriously affected.
We have seen many cases where people with salt pools where swimming in water with more than 8 ppm of chlorine thinking that they were doing something great for their health. The legal limit for chlorine in swimming pools to avoid health risks in Germany for example is at 0,5 ppm.
A third, and very interesting, method of disinfection is the use of ozone systems. The active disinfecting substance (O3) is created out of the surrounding air, so it is possible to install a system that requires no chlorine at all. High initial costs for this method are offset by the subsequent low maintenance required if the system is correctly designed . Yet there is a need for caution: ozone has an oxidising effect 20 times stronger than chlorine and so must be used with great care . All in all the application of ozone requires quite some specific experience.
We come now to Aguaconcept Lda's preferred method of disinfection the ultra-violet (UV) system. Here, pool water passes directly through ultra-violet light, which disinfects the water without any side effects and breaks down and eliminates chloramines . Still the addition of some residual chlorine is needed in order to avoid algae growth on the floor of the pool.
UV disinfection is highly effective. In tests on municipal pools with UV technology overall chlorine consumption was reduced by between 50 and 80%, with no increase in the level of bacteria. Lower overall bacterial counts can generally be expected, along with the reduction of spores (such as guardia and cryptosporidium, which are unaffected by chlorine and hypochlorite) and of legionella counts. The system will also remove organic substances through oxidisation. Finally, the UV system will produce water that really sparkles. It looks and feels wonderfully fresh and gives real pleasure to the swimmer in terms of both taste and feel (as well as satisfaction to the pool owner, thanks to lower operating costs and longer equipment life).
No matter which method of disinfection is used chlorine based, salt, ozone or ultra-violet all will need to be supplemented by the right amount of chloridic acid (acido cloridico) to maintain the water's chemical balance, represented by what is known as the pH value. The pH value should measure between 7.2 and 7.6 ideally. Liquid chlorine, for one, does not work outside these measures.
As the pH value in general has a tendency to rise, it has to be corrected from time to time by the addition of chloridic acid; diluted in water, it is harmless, with no side effects, and is the best and cheapest product with which to lower pH values. In some cases the water is acidic and the tendency of the pH is to sink which can easily corrected with sodium bicarbonate to bring it back up.
At Aguaconcept Lda., we recommend to use a good automatic pH and redox potencial control dosing system, which gently maintains the correct levels. With adequate container storage, it means an owner or supervisor can leave the pool untouched for some considerable time, without risk of a chemical imbalance occurring. It makes sense to spend that little extra, to get a really reliable system as there are many toys on the market that are just not worth the money.
The combination of a good automatic dosing system and the UV method of disinfection is guaranteed to ensure really clean, sparkling water, better health, lower costs and, not least, better protection for the environment. It's a winning, responsible and rewarding combination for pool owner and swimmer alike.
Check our website for more information: www.aguaconcept.com Aguaconcept Lda., Apt. 279, 8300 Silves Tel: 00351-282441313 Tlm: 916 356 633
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