We’re half way through the swimming pool season and we have seen some record breaking temperatures this summer which no doubt will have seen your swimming pool put to full use during the hot water but no sooner has the glorious sunshine gone to be replaced by record breaking rainfall and a drop in temperature, what a summer we have seen so far.


All of these changes put a real strain on the swimming pool water and all too quickly the water can lose its clarity and descend into a murky uninviting place to be, quick actions can rectify the situation, so what are the likely causes?


The following reasons are the likely symptoms for cloudy water.


  • Lack of / low sanitiser readings (Free Chlorine or Total Bromine)


  • Infrequent shock dosing during periods of heavy use / warm weather.


  • Algaecide hasn’t been topped or added


  • Filter efficiency is low / poor


  • pH out of balance


As you can see there is a long list of reason why water clarity is lost but all is not lost, the following remedies will help rescue the water so that you can enjoy swimming until the end of summer.


  • Check the chemical balance of your swimming pool on a daily basis (during hot weather check the balance 2 – 3 times per day) using an OPC Pool Tester


Ensure Free Chlorine doesn’t drop below 2 PPM (Parts Per Million) or if using bromine sanitiser Total Bromine readings drop no lower than 3 PPM (Parts Per Million)


pH readings should be between 7.2 and 7.5


  • Regularly undertake a shock dosing procedure (raising sanitiser levels), this will help eliminate the microscopic unfilterable waste which passes through the filtration systems. During periods of hot / warm weather when the swimming pool is in regular / heavy use consider shock dosing the water twice weekly.


If using a Chlorine sanitiser use OPC Chlorine Shock Granules or if using a Bromine Sanitiser use OPC Non Chlorine Shock Granules.


Always ensure bathers have left the swimming pool before adding chemicals to the water.



  • Filter efficiency is low / poor, when was the last time you backwashed the filter media or if using a cartridge filter when was this cleaned? During the peak season backwash the filter media weekly, this will help filter performance and also assist with water dilution; adding fresh water will always help water management. If using a cartridge filter remove weekly and clean with OPC Spa Cartridge Cleaner or OPC Spa Instant Filter Cleaner. These products will remove the build-up of oils, greases, mineral often found in cartridge filters.


To assist with the filtration process we recommend adding OPC Pool Sparkle or OPC Pool Clarifier to assist with the filtration process and to ensure water clarity is restored.


  • pH balance can often be a major factor to poor water clarity, when the pH reading is too high (above 7.5) chlorine efficiency reduces and often results in cloudy water. Check pH levels regularly (daily) and adjust pH readings using either OPC pH Minus to reduce pH readings or OPC pH Plus to increase pH readings.

Ensuring you have a pro-active approach to water care is the key to trouble free swimming pool water.

*Use biocides safely.  Always read the label and product information before use.