How to Treat a Green Pool

There are many reasons why your pool might be green. It may be due to no or low chlorine, green algae, dissolved metals, or you might have overstabilised your pool water.

No or Low Chlorine:

Chlorine is a sanitiser used to kill bacteria and algae. You can find chlorine at any of The Pool Team stores in the form of a floater, stabilised chlorine pills or granular chlorine.

There are two types of chlorine: Free chlorine and Total Chlorine. Free chlorine is the amount of chlorine that has not yet combined with contaminants which means that it is still available to sanitise the pool water.  The ideal range of Free Chlorine is 2-3 parts per million (ppm). Total Chlorine is a combination of free chlorine and chlorine that has already combined with contaminants.

For the best results, you should use an Aqua Pro Floater or Stabilised Chlorine Pills, both of which are kept in the pool to maintain the chlorine level. Granular chlorine can be used in addition to the floaters to maintain the Free Chlorine level within the ideal range. Learn more about Aqua Pro Floaters and Stabilised Chlorine Pills.

To get the most out of your chlorine, ensure that your pH and Total Alkalinity levels are in balance. Learn more about pH and Total Alkalinity.

There are different methods of adding chlorine to your pool and each has its own benefits.

• It can be added directly through the weir while on the filter setting. This method is slow releasing and therefore reduces the risk of spiking your pH.
• For a faster acting method, the chlorine can be diluted in a bucket of water and then added through the weir on the bypass/circulate setting. Be careful when diluting chlorine in water not to inhale the fumes.

The best time to add chlorine to the pool is in the late afternoon, avoiding the harsh sun. Remember to run the filter for 3-4 hours to evenly distribute the chlorine throughout the pool. The amount of chlorine to add is dependent on the size of the pool. Common practice is 1 cup per day for a 50 000 litre pool.

Green Algae:

There are different types of algae. Green algae floats around in the water making it cloudy and green. There is also green algae that’s slimy and attaches itself to the pool walls and floor.

Follow this step-by-step process to remove green algae:

1. Always remember to get the basics right first: Test the water; clean out the weir and pump baskets; backwash and rinse. This is to ensure that you obtain the best results from the products added. Learn more here.
2. Brush the walls and floor of the pool to loosen the algae from the surfaces.
3. With the pool system on bypass/circulate, add your Aqua Pro Algaecide through the weir, followed by the Aqua Pro Oxidiser.
4. After the oxidizer has been added, the pool may become cloudy. Run the filter for 12 hours.
5. Add the Aqua Pro Clarifier for a crystal clear pool. Learn more here.

Dissolved Metals:

There are always metals present in water. The metals in the pool water are constantly being built up over time in a variety of ways, such as adding certain pool chemicals, heavy rain, and the use of borehole water. When there is a high metal concentrate in the water and chlorine is then added, this can result in a green pool due to the chemical reaction between chlorine, copper and iron. To resolve this problem, follow this simple process:

1. Always remember to get the basics right first: Test the water; clean out the weir and pump baskets; backwash and rinse. This is to ensure that you obtain the best results from the products added. Learn more here.
2. Turn the system to bypass/circulate, add the Aqua Pro Metal and Stain Remover into the weir.
3. After the product has been evenly distributed in the pool, turn the system to filter and run for 12 hours.
4. Backwash and rinse to remove all the metals that are now caught in the filter.
5. Add the Aqua Pro Clarifier for a crystal clear pool. Learn more here.

Overstabilising:

Over stabilising is caused by continuous or overuse of products containing stabiliser. One of the most common causes of over stabalisation is not alternating between a stabilised and non-stabilised chlorine floater. Click here to learn about chlorine floaters. An overstabilised pool will render the chlorine and other chemicals less effective, causing your pool to turn green.

In order to counter over stabilisation, the pool water level needs to be lowered and replenished with fresh water. This will dilute the amount of stabiliser in your pool, slowly bringing it back into the ideal range of 40 to 80ppm.

The easiest way to lower the water level is by doing an extended backwash and rinse. Backwashing removes the water from the pool, reducing the water level, allowing for fresh water to be added. An extended backwash is done for approx. 5 minutes at a time. Do not drop the water level below the weir as this can cause damage to the pool pump. An extended backwash should be done daily for the first week, remembering to add fresh water after each backwash and rinse. After completing this process, take a sample of the water to one of The Pool Team stores to be tested. Or alternatively, use a home testing kit to test the water. If the stabiliser level hasn’t decreased enough then the process would need to be repeated until the stabiliser level is within the ideal range. If the stabiliser level is now within the ideal range, then continue with your normal pool chemical routine.

Head on down to any of The Pool Team stores for your complimentary water analysis which includes checking your stabiliser level.