Swimming Pool Chlorine

Swimming Pool Chlorine

Keeping your pool water chlorinated is essential to a healthy sparkling pool.  In our experience, most people are adding or generating excessive chlorine in their pools.  This leads to more acid demand, cloudy water, rising pH, calcium spots and clogged salt cells.  So, in the case of swimming pool chlorine, more is definitely not always better!

On the other hand, it is vital that there is sufficient chlorine in your pool water to keep it safe.  Insufficient free chlorine can make your water unsafe for swimming.  This is because the germs, algae and bacteria will thrive in low chlorine. Remember, Australian Standard 3633 suggests that safe pool water needs at least 1ppm of free chlorine.  However, we suggest that 2-3ppm be maintained just in case your chlorine levels drop due to rain or other factors.

The ‘cloudy water‘ page on our website also explains the relationship between pH and chlorine activity in the water. In short, high pH reduces the killing power of chlorine in your water, even if your test shows that your chlorine levels are correct! Therefore, if your pH is above 8.3 then the killing power of swimming pool chlorine is almost completely disabled. In short, we have cleared many of our client’s pools with constant algae problems by simply lowering the pH and not adding chlorine!


The video below offers information about the difference between combined, total and free chlorine levels in your pool.  It is a little technical in places but it is one of the most simple and best graphical explanations we’ve found.