What are the key aspects of creating and maintaining healthy pool water? Firstly, what do we mean by ´´healthy´´. Actually, we´re not just talking about a sparkling blue pool, because that can at the same time be a dangerous chemical soup, but we mean a clean pool with the minimum levels of harmful chemicals in water that is free of bacteria and algae.
There are two main mechanisms by which pool water is kept clean. The first is literally the physical cleaning and the second is the chemical or disinfection process. There is a third aspect that underpins the effectiveness of the these processes and that is the water chemistry, primarily the pH level, in simple terms the hardness or softness of the water (see´´More Chemistry¨ below for bed time reading).
(In fact we do hope you do read this but if it all gets a bit daunting, call us and enquire about our training lessons that´ll enable you to take control of your pool and save money!)
This is the process indicated in the diagram, right, water being pumped and circulated through, normally a sand filter, and literally being stripped of debris and bacteria. This is topped up by some manual labour (the pool cleaner, human or robot) in vacuuming, backwashing and brushing the pool.
In combination with physical cleaning, disinfection also keeps your pool free of algae, bacteria, viruses and micro organisms. The most common method is to use manufactured chlorine in tablet form that normally, placed in the skimmer, slowly dissolves into the pool water during the filtration cycle. But of course, it has to be at a safe and comfortable level for the swimmer – too much for example can do more damage to us than bacteria. It is an excellent disinfectant but, as we have all experienced, it can have adverse effects such as irritation to the eyes, aggravation of skin complaints and, with prolonged contact or high levels, can change the colour of your hair. There are more aspects to chlorine, such as its different forms and why a pool smelling of chlorine is not good news…but for now, suffice to say the monitoring and careful application of chlorine levels is vital.
As for chlorine, measuring the pH on a regular basis is equally important in achieving a healthy pool water for both swimmers and the pool equipment. The pH level is a measure of the alkalinity-acidity and controlling this parameter is key to providing the optimum conditions for the disinfection process outlined above. As the pH level rises (which in this area can be normal) the effectiveness of the chlorine reduces and, typically with a pH level of 7.8, 75% or three quarters of the chlorine content is being wasted because it is not able to work. Furthermore, again important in this area, maintaining the right pH level reduces the calcium (limescale) crustation on the pool surfaces and safeguards the equipment in the pump room.
Normally the pH level is controlled by adding pH- (a form of acid in the form of sodium bisulphate) in a granular form, measuring the quantity to be added appropriate to the pool size, mixing in a bucket of water and then applying directly to the pool water using the jets to help disperse the chemical throughout the pool. The pH level can change daily and has a tendency to rise, influenced by factors such as temperature, addition of chemicals or debris, and therefore requires regular attention to maintain the pool water in good condition particularly in the summer season with high temperatures, use of the pool and refilling.