Everything you need to know about swimming pool chemicals
Why is maintaining the pH, chlorine and alkalinity of a pool so important?
It is vital to have a basic understanding of the chemicals you often hear mentioned regarding effective pool maintenance – regardless of whether your pool has already been fitted with a disinfection system. The three most important ones to remember are ‘pH’, ‘chlorine’ and ‘alkalinity’.
pH
pH describes how acidic or alkaline the pool’s water is. The ‘pH scale’ is a two-way scale centred around the number 7. Water with a pH of 7 is said to be neutral, meaning that it is neither acidic nor alkaline. Values below this value are acidic, whereas values higher than this are alkaline. When it comes to swimming pools, the ideal pH is between the range 7.2 and 7.4.
Maintaining the pH between this range is important for a number of reasons. Firstly, a pH that is too high or too low could damage the fabric of pool equipment. In hard water areas, scale can form much more easily at higher pH levels, so this too could damage pool equipment. Moreover, the pH level can seriously impact bather comfort. If the pH is too high or too low, the bather could suffer from eye, nose or skin irritation.
Thanks to high-quality modern test kits and swimming pool chemicals, maintaining your pool’s pH is fairly straightforward. If the pH level falls too low, simply add Compass Pool’s pH Plus; if it becomes too high, use Compass Pool’s pH Minus. The amount you need to use will be clear from the dosage instructions on the label.
Do not add in a lot of chemical in one hit, otherwise the pH value will swing rapidly in one direction. Use small doses to get your pH level within the desired range both quickly and easily.
Chlorine
Chlorine is an extremely effective bactericide and oxidiser, hence why it is so commonly used across many water treatments. It is also the most widely available product for sanitising pool water.
Adding chlorine to your pool ensures that the pool’s water is properly sanitised and safe to swim in. Chlorine also leaves a residue in the water, so it maintains its germ-killing function even when your filter system isn’t on.
You will often come across the terms ‘total chlorine’, ‘free chlorine’ and ‘combined chlorine’ when it comes to pool maintenance, which can sometimes confuse pool owners. Here is what each term means:
- Total chlorine. As the name implies, this indicates the total amount of chlorine contained in your pool water, but doesn’t tell you how effectively it is killing bacteria. The ideal total chlorine value should be between 8ppm and 2.5ppm.
- Free chlorine. This is the most important value, as it relates to the chlo