5 keys to maintaining water quality in your pool

If it is not properly maintained, the water quality in your domestic swimming pool may contain a range of germs, including bacteria and viruses. Some germs can cause health problems, such as ear, nose and throat infections.

You should check your swimming pool regularly to make sure that the water is safe for swimming. A simple way to do this is to look into the pool each day and check:

  • Is the water clear?
  • Can you see to the bottom of the pool?
  • Does the water look any different to how it looked the day before?

Any changes, such as cloudiness, mean you should test the water and take any necessary steps to improve water quality before anyone goes swimming.

Swimming pool maintenance

The five keys to maintaining water quality in your swimming pool include:

  • filtration
  • sanitisation
  • pH level
  • total alkalinity (TA)
  • calcium hardness

1. Swimming pool filtration

The water in your pool is pumped through a filter to remove debris and particles. How long you need to run the filter depends on the size of your swimming pool and the horsepower of your pool pump. If you are unsure, check with the manufacturer or consult with a pool maintenance professional.

Most pool filtration systems are not able to filter all the water in the pool. Chlorination is a common and effective treatment often used alongside filtration to inactivate microbes that may be present in the pool water. The best-maintained pools rely on multiple treatment barriers.

2. Sanitisation for swimming pools

Bacteria is a serious health risk and needs to be killed quickly and effectively. Adding a sanitiser to the water at recommended levels will do just that.
Dead bacteria are removed by the filter and the residual sanitiser left in the water will kill any new bacteria. Most bacteria will be killed when exposed to a residual sanitiser, provided recommended levels are maintained.

Chlorine was the typical standard sanitiser for domestic and public swimming pools but can be hazardous and difficult to manage. The past twenty years has seen salt chlorination (chlorine) become the standard, but the past few years have also seen the introduction of Chlorine Free Sanitisers such as the use of Ozone or Silver/Copper such as the NKD-R Freshwater System.

You should do your research and talk to your pool builder about the right sanitising option for your pool based on construction, location and its use. Check out the SPASA website to learn about some of the other options.

3. pH level in swimming pool water

The pH level indicates how acidic or alkaline the water is at any given time. A pH level of 7 means that water is neutral; above 7 means the water is alkaline, while below 7 indicates acidity. Aim for a pH level of between 7 and 7.6. If the water pH is higher than 8, anyone who swims in the pool is at risk of skin rashes, while a pH of lower than 7 can sting swimmers’ eyes.

Some of the many factors that can affect your pool’s pH level include heavy rain, the number of swimmers in the pool and chemicals. Remember to regularly check the pH level.

4. Total alkalinity and swimming pools

Total alkalinity means the sum of all alkaline chemicals in your water. If the total alkalinity is too low, the pH balance can become unstable. Concrete and painted pool surfaces will also deteriorate over time. The total alkalinity and pH are interconnected. For example, raising the total alkalinity could also raise the pH. Make sure you don’t disrupt your pool’s pH when adjusting the total alkalinity and vice versa.

5. Calcium hardness in swimming pool water

Calcium hardness refers to the amount of mineral calcium dissolved in your water. Low calcium levels will deteriorate pool surfaces, while high calcium levels will leave a ‘scum’ or scale on surfaces and equipment.

Consult a pool professional for information on how to maintain good water quality in your swimming pool. Ways to maintain pool water quality may include:

  • checking pH and chlorine levels daily. Preferably before the first swim of the day to make sure the water quality hasn’t altered overnight.
  • checking the pH and chlorine twice daily in very hot weather.
  • monitoring chlorine levels in heated pools which need more chlorine than non-heated pools.
  • brushing and vacuuming your pool on a regular basis.
  • regularly checking the pump, skimmer boxes and other pool equipment, and repair or replace parts as necessary.

Things to remember about water quality

  • People swimming in the pool are the main source of contamination.
  • The keys to maintaining water quality in your swimming pool include filtration, chlorination, pH level, total alkalinity (TA) and calcium hardness.
  • Check your pH and chlorine levels daily – preferably, these tests should be done before the first swim of the day to make sure the water quality hasn’t altered overnight.