Why is My Pool Water Green? Causes and Solutions

Pool water green is not just an eyesore but can also be a sign of potential health hazards. No one wants to be near these pools or to swim in the green pools. With the passage of time, bacteria and green algae start growing in the pools and turn the water green. In this article, we will discuss the causes and find effective solutions that can help restore pool water to its crystal-clear state.  

Causes of Pool Water Green  

Pool water green can be caused by:  

Algae Growth  

Algae development is the main cause of pool water green. Algae are microscopic plants that thrive in water, particularly when the pool's chlorine levels are low or the chemical balance is off. Once algae begin to grow, they can quickly turn your pool water from blue to green.  

Low Chlorine Levels  

Chlorine is essential for keeping pool water sanitized. When chlorine levels drop below the required amount, it can’t effectively kill off bacteria, algae, and other contaminants. This can lead to algae blooms, which turn the water green. Regularly checking and maintaining chlorine levels is crucial to prevent this issue.  

Imbalanced pH Levels  

Your pool’s pH level should be kept in a specific range (between 7.2 and 7.6) for optimal water quality. If the pH is too high or too low, it can affect the chlorine’s ability to do its job. This imbalance creates the perfect environment for algae growth, turning your pool water green.  

High Phosphate Levels  

Phosphates can enter your pool water through organic debris, such as leaves, grass, and dirt, or even from rainwater. They serve as food for algae, helping them to thrive. If phosphate levels are high, algae can flourish even if your chlorine levels are sufficient, turning your pool water green.  

Metals in the Water  

Sometimes, metals like copper or iron can cause your pool water to turn green. Copper, in particular, can oxidize when it comes into contact with chlorine, giving the water a green tint. Metals may enter your pool through the water source or from corrosion in pool equipment.  

How to Fix Pool Water Green  

If your pool water has gone green, you don't have to worry at all. The problem can be resolved effectively. Here are some possible solutions to this issue.  

Shock the Pool  

One of the most effective ways to clear pool water green is to shock the pool. Shocking involves adding a large dose of chlorine or a non-chlorine shock to kill algae and other contaminants. Use a chlorine shock with a concentration of 70% or higher to ensure maximum effectiveness. After shocking the pool, let the filtration system run for at least 24 hours to help clear the water.  

Brush and Vacuum the Pool  

Algae can cling to the walls, floor, and other surfaces in your pool. After shocking the water, it’s important to scrub the pool thoroughly to remove any remaining algae. Use a pool brush to clean the walls and floor, and then vacuum the debris out of the pool. This will prevent algae from regrowing and turning the water green again.  

Balance the Water Chemistry  

Once the pool has been shocked and cleaned, test the water's chemical levels. You’ll need to ensure that the pH, alkalinity, and chlorine levels are within the proper range. Use a pool water test kit or take a sample to your local pool store to get an accurate reading. Adjust the chemicals as needed to maintain balance and prevent future algae growth.  

Add an Algaecide  

While shocking the pool and balancing chemicals are key to getting rid of pool water green, adding an algaecide can provide an extra layer of protection. Algaecides help to kill off any remaining algae spores and prevent new ones from forming. Be sure to follow the manufacturer’s instructions on how much to use based on your pool size.  

Clean the Filter  

After treating your pool, your filter may become clogged with algae, dirt, and other debris. A dirty filter will hinder the circulation and cleaning process, making it harder to keep your pool clear. If you have a sand or DE (diatomaceous earth) filter, backwashing it will help remove the buildup. If you use a cartridge filter, remove it and clean it thoroughly before placing it back into the system.  

How to Avoid Green Pool Water  

Follow the tips below for maintaining pool water to keep your pool clear and balanced all season.  

Regular Water Testing  

Prevention starts with consistent monitoring of your pool's chemical levels. Test the water at least twice a week during the swimming season, ensuring that the chlorine, pH, and alkalinity levels are in the appropriate range. This will help you catch any imbalances before they cause a problem.  

Keep the Pool Clean  

Regular cleaning is crucial for preventing algae growth. Use a pool skimmer to remove leaves, debris, and other organic matter from the water. Brush the walls and floor at least once a week to prevent algae from taking hold.  

Use a Phosphate Remover  

If your pool is prone to algae growth, consider using a phosphate remover. Since phosphates are algae’s primary food source, removing them from the water will help prevent algae from growing. You can purchase a phosphate remover from most pool supply stores.  

Monitor Metal Levels  

If metals in the water are contributing to the green color, consider using a metal sequestrant. This chemical binds to metals and prevents them from reacting with chlorine, which can help keep the water clear. You may also want to have your water tested for metals if you suspect they are an issue.  

Where to Buy Chemicals to Treat Green Pool Water   

Dong A Chemical is a leading factory in Vietnam that specializes in providing water treatment chemicals for swimming pools. As a trustworthy address for many customers, Dong A ensures that all water treatment chemical products meet high-quality standards and have clear origins. Besides, when you buy from Dong A, you also enjoy the best prices on the market.  

Hopefully, with the information shared in this article, you know how to treat  pool water green .  If you need to buy a product, please contact us via hotline (+84) 985797941 immediately for advice and the best price quote.