pH and Fibreglass Pools

November 8, 2023

The relationship between chlorine and pH is of utmost importance in maintaining a clean and safe swimming pool. Chlorine plays a vital role in pool sanitation by effectively killing bacteria, viruses, and other harmful contaminants in the water which in turn ensures that the pool remains clean and free from harmful microorganisms.

The efficiency of chlorine is strongly influenced by the pH level of the pool water. pH is a measurement of the water’s acidity or alkalinity, ranging from 0 to 14. The ideal pH range for a swimming pool is between 7.2 and 7.5. When the pH level deviates from this range, it can significantly impact the effectiveness of chlorine, and thereby the pool cleanliness is compromised.

If the pH is too low (below 7.2), the water becomes acidic. In such conditions, chlorine rapidly dissipates and loses its effectiveness, leading to inadequate sanitation. On the other hand, if the pH is too high (above 7.5), the water becomes alkaline. In alkaline conditions, chlorine becomes less active, resulting in poor sanitation and the likelihood of harmful bacteria and algae growth.

By keeping the pH within the recommended range, pool owners ensure that chlorine can work optimally, providing a clean and safe swimming environment for all pool users.

Regular testing and maintenance

pH test strips are a convenient and widely used method for monitoring pH levels in pools. Composed of specially treated paper or plastic, test strips contain chemical indicators that change colour in response to the pH of the water applied, allowing individuals to determine the pH level quickly and accurately.

Step-by-step guide for testing pH with test strips

  1. Dip the test strip into the pool water at the recommended depth and hold it in the water for a few seconds.
  2. Remove the test strip from the water and shake off any excess water.
  3. Wait for the time specified on the test strip packaging for the colour reaction to occur.
  4. Compare the colour of the indicator pads on the test strip to the colour chart provided on the packaging to determine the pH level of your pool water.

Interpreting pH Test Strip Results

The colour that the test strip indicators change to will correspond to a specific pH value on the chart. By comparing the indicator colours to the chart, you can determine the pH level of your pool water. If the pH falls within the recommended range of 7.2 to 7.5, the water is appropriately balanced. If the pH is below 7.2, the water is too acidic, while a pH above 7.5 indicates alkalinity. Taking corrective actions to adjust pH levels when they are outside the optimal range will help maintain the water’s clarity and prevent potential complications associated with imbalanced pH levels.

Additional Tips for pH Maintenance

  1. Maintain proper alkalinity levels: Alkalinity acts as a buffer, helping to stabilise the pH. Ensure that your pool’s total alkalinity is within the recommended range (80-120 ppm) to support pH balance.
  2. Balance other water parameters: Along with pH, it’s important to monitor and maintain other water parameters such as calcium hardness and total dissolved solids. Imbalances in these parameters can affect pH levels.
  3. Keep pool equipment clean: Scale and debris buildup in pool equipment can impact pH levels. Regularly clean and maintain filters, pumps, and other equipment to ensure optimal function.
  4. Follow supplier’s instructions when adjusting pH levels using chemicals. Handling chemicals with care and using them properly is essential for your safety and accurate pH adjustment.

Lowering pH levels using hydrochloric acid (also known as muriatic acid)

Requires caution and proper handling. Here is a step-by-step guide on how to safely lower pH using hydrochloric acid:

Safety Precautions

  1. Put on protective clothing, including gloves, goggles, and a face mask. Work in a well-ventilated area to minimise exposure to fumes.
  2. Determine the current pH level using test strips or a pH testing kit. Calculate the amount of hydrochloric acid required.
  3. Never add water to the acid; always add the acid to the water. Fill a clean plastic bucket about halfway with water. Slowly pour the required amount of hydrochloric acid into the water, stirring gently with a non-metallic object. Avoid splashes or spills, as hydrochloric acid is highly corrosive.

Acid addition

Turn off any pool equipment, such as pumps and filters, to prevent acid damage. Gently pour the diluted acid solution into the pool at different points around the perimeter while walking slowly. Avoid pouring the acid solution directly onto pool surfaces or near pool equipment to prevent damage.

Turn on the pool filter to circulate and turn the pump on. To allow the acid solution throughout the pool. Allow the water to circulate for about 1-2 hours. Retest and Repeat if necessary.

Increasing the pH level in a fibreglass swimming pool

This can be achieved by raising the alkalinity level. Alkalinity acts as a buffer, helping to stabilize pH and prevent fluctuations. Here are some steps to increase alkalinity and, in turn, raise the pH level in a fibreglass pool, using metric measurements.

  1. Test the alkalinity level: Use a pool test kit to measure the current alkalinity level of the pool water. The desired range for alkalinity is typically between 80-120 ppm (parts per million).
  2. Add alkalinity increaser: Based on the test results, calculate the amount of alkalinity increaser needed according to the manufacturer’s instructions. Typically, you’ll need around 1 kilogram of alkalinity increaser per 50,000 litres of pool water to raise alkalinity by 10-15ppm and raise the pH.
  3. Dissolve and distribute the increaser: Dissolve the calculated amount of alkalinity increaser in a bucket of water according to the instructions. Slowly pour the solution into the pool while the pump is running to ensure even distribution.
  4. Monitor and retest: After adding the alkalinity increaser, retest the alkalinity and pH levels using a test kit. Repeat the process if necessary to achieve the desired alkalinity and pH range of 7.2-7.5

Remember to always follow the manufacturer’s instructions, wear protective gear, and maintain proper pool safety protocols when adding chemicals to your pool. If you’re unsure of your next steps, it’s worth contacting your local professionals like Poolwerx for some guidance. It could save you hours (and money) in the long run.