What does chlorine do and why is it SO important?

Chlorine is the waters sanitation in a swimming pool. Without chlorine to sanitise the water, bacterial growth will be abundant in the water leading to health issues from swimming in the water.

There are a number of different sanitisers available in the marketplace;Liquid Chlorine (Sodium Hypochlorite)

  1. Calcium Hypochlorite (Cal-Hypo)
  2. Lithium Hypochlorite (mainly used in spas)
  3. Salt Chlorination
  4. Magnesium Chlorination (NEW)
  5. Bromine (mainly used in spas)
  6. Ozone (chlorine or bromine still required)
  7. Ionisation (chlorine still required)

The role of a sanitiser (or disinfectant) is to destroy bacteria as quickly as it is introduced into a pool. The sanitiser must be continually present in the water in a measurable and active residual amount to do this. Between 2-3 ppm (parts per million) is the ideal range for chlorination.

Possible affects of low sanitiser levels;

  • Unsafe water (bacterial growth)
  • Cause of ear, throat and bowel infections etc
  • Algae bloom – cause of green, mustard and black spot algae
  • Cloudy water – build up of contaminants
  • Build up of chloramines
  • Cause of eye, skin irritations
  • Smelly water

People often assume because they can smell chlorine that there is plenty of chlorine in the water – this assumption is WRONG. The smell of chlorine is actually chloramines (trihalomethanes), which are carcinogenic. These chloramines cause sore eyes and a strong chlorine smell and are the result of a lack of chlorine.

The waters PH level can also affect a pool or spas sanitation levels. The higher the PH level the less efficient the sanitiser will become. A PH level of 7.4 is chosen as the ideal because it is the best compromise between having a sufficient percentage of chlorine present as hypochlorous acid (the killing form of chlorine) and it is non-corrosive towards swimmers, pool surfaces and equipment.