The 6 Most Common Reasons Why Your Pool Is Turning Green

24 May, 2024

We’ve all had that moment of wanting so desperately to plunge into a cold refreshing pool on a hot summers day, only to be met with disappointment. Instead of the crystal-clear blue water that you were expecting, your pool looks more like a swamp – cloudy and a repelling shade of green that makes you want to avoid it altogether. This scenario can be quite confusing and obviously frustrating for pool owners. The question then clearly arises: “Why is my pool green, and how can I fix it?”

This blog will talk about the main reasons behind green pool water and offers solutions as to how to overcome it, to help you restore your pool to its previous clean state. By understanding these reasons that cause it and the corresponding treatments, you can save yourself valuable time, financial resources, and frustration.

Understanding The Cause of Green Pool Water

The most likely and common reason that your pool water has turned green is probably algae growth. Algae are very small living things, kind of like plants, that love water with plenty of things for them to eat. So, if your pool turns green, that possibly means the algae have found a happy home and multiplied quickly in your pool. It’s confusing, so here are a few things that can cause this to happen:

1. Sunlight Exposure: Just like us humans, algae love to soak up in the sun. Which is why pools that get a lot of direct sunlight are more likely to become infested with algae.
2. pH Imbalance: Sustaining a proper pH level is also very important for your swimming pool. Algae loves water with a high pH. A high pH may be above 7.6. This level reduces how effective chlorine usually is. With the primary disinfectant not effectively working, algae can flourish. The main suggestion is regular testing and adjustments of your pool’s pH level so that the pool remains the perfect shade of blue that you want.
3. Clogged Filters: Your pool’s filtration system is important because it filters out dirt, sand and organic materials to leave your pool sparkling. If this system malfunctions, it may keep harmful materials like dirt, sand, and organic matter in pool water. This might promote algae growth leading to a green colour appearance on pools. To avoid this, you have to clean it more often through regular checking by professionals who know well how those machines operate.
4. Low Chlorine Levels: Sustaining a clean pool necessitates maintaining the right level of chlorine which ranges from 1-3 ppm. Algae spores and bacteria are directly removed by chlorine. When chlorine levels drop due to heavy use, rain dilution, or poor maintenance, algae can take advantage and multiply, turning your pool green. Regular testing and chlorine adjustments are essential to prevent this and keep your pool sparkling.
5. High Phosphate Levels: Phosphates are nutrients that algae readily consume. Many things can cause them to get in your pool like fertilizers, detergents, decaying leaves among others. Chlorine is ineffective against algae growths when phosphates exceed 500 parts per billion (ppb). This control prevents green coloration of the water thus making sure that it remains healthy.
6. Too Much Cyanuric Acid: People, sometimes, add a stabilizer to chlorine – cyanuric acid – for it to remain for a long duration under the sun. However, too much stabilizer over 50 ppm) can backfire. Even if it seems like there’s enough chlorine, it does not work properly. This creates ideal conditions for algae to thrive, and therefore it is important to monitor the levels of cyanuric acid at all times and make the necessary adjustments to prevent an excess.

Types of Algae and How to Identify Them

Being able to tell which type of algae it is makes it easier to treat. Green algae usually respond well to regular chlorine and brushing. Mustard algae need specific algaecides, and black algae call for some heavy-duty scrubbing and strong chemicals. Getting it right when identifying the algae means the treatment will be more effective and efficient.​

Steps To Keep Your Pool Clean

1. Test and Balance the Water Chemistry:
   • Grab your pool testing kit. It will be used to test key factors including pH, chlorine, alkalinity. To obtain results that are precise, it is important to pay close attention to the instructions given by the kit.
   • Once you have your test results, compare them to the recommended ranges. These are usually printed on the kit or readily available online from pool supply stores.
   • If any levels fall outside the recommended range, take action!  For example, if your pH is high, you’ll need a pH decreaser to bring it down. Similarly, low chlorine might require adding chlorine shock or stabilizer.
2. Shock Treatment – Pool shock treatment is a very efficient way of removing algae, bacteria, and other unwanted elements from the water in your pool. Here is what you should do before you start:
   • The first thing that you need to do is to find out the quantity that is required for you to shock your pool. This relies on the size of your pool; therefore, it would be better if you read through the directions provided on the product.
   • Ensure that your pool’s circulation system is functional. Shock treatment needs proper circulation so that it can be distributed evenly throughout.
   • Sprinkle the shock treatment evenly around the edge of the pool, avoiding dumping it all in one spot.
   • After adding the shock treatment, let it circulate for several hours, or even overnight, before taking a dip. This allows the shock to effectively eliminate contaminants.
   • Once the waiting period is over, test your chlorine levels again. Shocking can sometimes affect chlorine levels, so adjustments might be necessary. Try to maintain a chlorine level that is usually 1-3 ppm. It is important to aim at it because that is the recommended range.
3. Brush and Vacuum – Manual cleaning plays a vital role in maintaining a sparkling pool. This not only improves water clarity but also prevents further algae growth.
   • Grab your pool brush and give your entire pool a good scrubbing! Walls, floors, and steps, all included. This loosens any algae or gunk clinging to the surfaces.
   • Especially in the corners, steps and those hidden stops – that’s where algae like to hide. Give those areas some extra scrubbing.
   • Now that you have scrubbed and loosened all those algae and debris, use your pool vacuum to suck the remains all up from the pool bottom.
4. Increase Filtration and Circulation:
   • Give your pool filter a regular cleaning! How often depends on your filter and manufacturer’s instructions.
   • Over time, your pool filter media gets dirty and needs replacing. Replace it as needed to ensure that it works effectively.
   • Make sure to run the pool pump and filter for enough time each day, often 8 hours. This helps make sure that there is circulation in all parts of the pool so that the filter can catch the dirt properly.
   • Think about using a pool skimmer. It helps remove leaves, bugs, and other floating debris from the surface. This keeps your water cleaner and circulation stronger.
5. Regular Maintenance
   • Schedule regular brushing and vacuuming sessions to keep pool surfaces clean.
   • Test the water chemistry weekly using a testing kit. This allows you to monitor key factors like pH and chlorine levels. If any levels fall outside the recommended range, simply adjust them.
   • Be sure you check and clean your pool skimmers, filters, and pumps regularly in order to make them function better which in turn will enable you to maintain a clear pool.
   • Keep an eye out for green water or discoloured patches on the pool walls. These can be signs of algae. Catching it early makes it easier to get rid of.
     
     

Conclusion

A green pool is not desired by anyone. Luckily for you, by following these simple steps, you will soon be happily enjoying your nice and blue pool. You can unlock the secrets to having a clear and inviting pool all year long. Testing regularly and spending a little time cleaning will enable you to reach the right chemical balance without any traces of algae growth on it. In addition to this, clean filters and proper circulation are what you need in order to guarantee high quality water in your swimming pool. By following these steps, you can keep your pool at a low risk for algae growth.

References

https://www.homesandgardens.com/gardens/green-algae-in-a-pool

https://www.bobvila.com/articles/why-is-my-pool-green

https://www.armandhammer.com/en/articles/why-is-pool-water-green-how-to-fix

https://www.asppoolco.com/blog/2022/november/green-pool-problems-how-to-clean-a-green-pool-fa

https://www.bunnings.com.au/diy-advice/outdoor-living/pools-spas/how-to-fix-a-green-pool

https://dengarden.com/swimming-pools/How-to-turn-your-swimming-pool-from-green-to-clean

https://www.thespruce.com/why-your-pool-is-green-6745501

https://www.wikihow.com/Get-Rid-of-Green-Water-in-a-Swimming-Pool

https://www.self.com/story/should-you-swim-in-a-green-pool

https://www.lowes.com/n/how-to/get-rid-of-pool-algae