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SPN AUG 2011 WaterTesting
www.swimmingpoolnews.co.uk WHY ARE PROFESSIONALS
HESITANT TO TEST WATER? There’s no shortage of equipment which produces fast and accurate analysis of swimming pool water. Ease of use and accuracy are still the important criteria but what is worrying the industry is that too many pool professionals are reluctant to make use of these products
By Alan Lewis T
he best route for crystal clear water is linked with the ability to regularly test its quality and to do so with systems which are easy to use and have the highest possible level of accuracy. There’s a range of quality systems on the market which makes the choice straightforward for pool owners and managers. Regardless of the system and product, whether it be tablet, strip or a digital option the real benefit is they can eliminate the ‘guesswork’ as to what state the pool water might be in.
What worries the industry as a whole is that some service professionals are still hesitant to use them, perhaps because they don’t understand how these systems work.
The pH in a swimming pool is the single most important parameter, so to test it accurately is a priority. Testing methods on the market vary from test strips and phenol red tablets to digital photometers and pH meters. Of these a pH meter
is acknowledged to be the most accurate, fast and easy to use method. It uses no reagent but gives an instant digital readout across the full pH scale. The move to more sophisticated and accurate swimming pool test kits should have one target – to provide test results that would normally be associated with laboratory analysis undertaken by trained technicians.
Tom Palin pioneered the DPD method for measuring chlorine levels and this system remains the mainstay in testing today. The systems and methods of testing, however, have developed in terms of technology.
Traditionally, measurements were made using a colour comparison system, such as the Tintometer Lovibond 2000+, still used today. The ‘fixed colour’ glass Comparator still offers accurate and reliable testing even in today’s high- tech environment.
However, there was increasingly a need for more accurate systems. The photometer was
born and today offers features such as single button operation; full waterproofing and memory and download facilities.
Many assume free chlorine is the most important parameter. If the pH level is too high, the chlorine simply will not work. Instead, bacteria will flourish and swimmers will be put at risk of serious infection.
The optimum level for pH in a pool is around 7.2. If, however, the level rises significantly above this, free chlorine becomes inactive and will not work. The danger is that it will still show as being present in the water. For example, a free chlorine level of 3ppm would indicate that the pool is safe and protected for swimming. However if the pH has risen to around 9 or 10, the chlorine will be unable to function, bacteria will start to thrive and the water will become unsafe for swimming. For some of the parameters regularly measured in pool and spa water, an analysis can be performed with the simple push of a button.
HOW TO ACHIEVE HASSLE FREE WATER TESTING
Those who run a professional swimming pool or spa know how important good and accurate testing of the water is. Those who own a domestic pool are keen to ensure it is kept fully functional and pristine clean. Good measurement and control of the quality of the water are essential not only to the water’s appearance. More importantly it plays an essential role in the consideration of bather comfort and safety. Regular and careful analysis also helps in the control of chemicals, keeping costs down, and the protection of the plant / pool and its equipment.
There are several options out there for water analysis equipment. First and foremost, none of the options is wrong. However, some are more appropriate to specific application. Therefore, before
selecting which system to use and before embarking on the testing itself, it is important to consider the options available and select the method most suited to your needs. At the very least, the following considerations should be taken into account: • The tests you need to carry out – which parameters are you looking to measure?
• At the lowest level, chlorine (or bromine for spas), pH values and alkalinity are typical.
• The more discerning analyst may wish to test for Balanced Water – Langelier Saturation-Index.
• The accuracy required to meet operating procedures.
• This is of particular importance for pools / spas utilised by the public.
• Do the results need to be recorded for potential audits?
• Where the tests will be carried out? • Who will be doing the testing?
Once a response to these questions has been found, you will probably be faced with one of the two following alternatives: a visual comparator or an electronic photometer based system. Each method has its own respective advantages and disadvantages.
COMPARATORS
Comparators are visual instruments that use a series of discs with continuous colour scales to take a measurement. By adding a chemical to the water (powder or tablet), a colour change is induced, enabling a visual match to be made and a reading taken. These easy-to-
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