Understanding the best way to keep your pool chlorinated is essential to a healthy sparkling pool. In our experience, most people are adding or generating excessive chlorine in their pools and this leads to more acid demand, poor water clarity, rising pH, calcium formation on walls and floor, clogged salt cells and high dissolved solids in your water. In the case of chlorine, more is definitely not always better!
On the other hand, it is vital that there is sufficient chlorine in your pool water to sanitise it and keep it safe for swimming. Too little, or no free chlorine can make your water unsafe for swimming as the germs, algae and bacteria will thrive in the water if there is insufficient chlorine levels. Australian Standard 3633 suggests that safe pool water must maintain at least 1ppm of free chlorine. We suggest that 2-3ppm be maintained year round in the pool just in case your chlorine levels drop due to rain, bather load 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! If the pH is above 8.3 then the killing power of chlorine is almost completly disabled. We have cleared many of our client’s pools with constant algae problems by simply lowering the pH levels 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.