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SPN AUG 2012 WaterTesting
www.swimmingpoolnews.co.uk
There are no excuses for not correctly, regularly and precisely testing the quality of swimming pool water. Pool water testing products are sophisticated and accurate, offering applications and budgets for every pool operation. Manufacturers continue to refine and improve their products but the key for carrying out the testing is the correct training, knowing how to use the equipment and reacting to any problem
F
alse positives, phantom results, chemical interference, turbidity, reagent sensitivity, reagent shelf life, high levels of chlorine, monochloramines, organic chloramines, disinfection by-products and your eyes all contribute to whether you get a good reading when you test the water in a swimming pool. That’s the bad news.
The good news is that as technology continues
to provide further options for manufacturers to refine and improve their testing products, so the process becomes easier and more accurate and more likely to override any complications. There is a mantra which those testing water would do well to remember. It is read-record and react – a simple enough summary of what is necessary, irrespective of the product you are using or the water testing circumstances.
“There is no perfect water testing system or product. It is just that some are more appropriate to what accuracy you are looking for, what you need to measure and whether the results need to be recorded”
CRITERIA TO DECIDE BEFORE YOU MAKE YOUR TEST PRODUCT CHOICE?
• What tests do you want to carry out – which parameters are you looking to measure?
• Chlorine (or bromine for spas), pH values and alkalinity should be the absolute minimum to test for.
• A more thorough approach might be to test for Balanced Water – the Langelier Saturation-Index.
• What degree of accuracy are you looking for?
• Do you have a budget for your water testing programme?
• Are the test results for you or you need to prepare them for a more formal audit of the pool?
There is no perfect water testing system or product. It is just that some are more appropriate to what accuracy you are looking for, what you need to measure and whether the results need to be recorded.
There is still a suspicion that some service professionals are still hesitant to use them, perhaps because they don’t understand how these testing systems work.
If anyone doubted the importance of proper testing of swimming pool water then two events before last Christmas served up perfect reminders.
Two cases of cryptosporidium closed public swimming pools. Cases of gastroenteritis were reported.
Public health inspectors were called in after reports from doctors about illness and diarrhoea, investigations were launched and both pools were forced to close amidst newspaper and television coverage.
The pools in Glasgow and Wells in Somerset
remained closed while tests took place and the quality of the water could be assured. One view is that the public should lead the way in making sure pool water is tested properly and demand to see audits of testing at their local pool. Supporters of this approach argue that test strips or photometers take such a short time to see whether or not the water is safe that it is reasonable for any swimmer to ask for the pool water to be tested before getting in. 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. Traditionally colour comparison systems, such as the Lovibond 2000+, were used to give accurate and reliable testing even in this more high-tech environment.
The DPD colorimetric method of testing for free chlorine and total chlorine was being worked on in the 1940s and a commercial product was first introduced by Tom Palin in 1957 in the United Kingdom. It has been modified several times over the years and studied almost continuously. For years DPD was a dry reagent and packaged as a tablet or powder. Today, the most common form is liquid DPD. It measures the free chlorine as well as pH, combined chlorine, hardness, cyanuric acid, and alkalinity. It’s also called the ‘pink test system’ due to the chlorine which becomes pink.
The importance of testing water in pools where the public were swimming kick started the need for a more accurate objective system. So the photometer was born offering features such as single button operation; full waterproofing; memory and download; and covers all the essential pool water tests.
Regardless of the systems and products now available, whether it is a tablet, strip or a digital
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