Poolking, your best swimming pool equipment manufacturer and supplier with more than 20 years experience.                                                                              +8613922334815


why is my pool filter green


Why Is My Pool Filter Green?

If you've noticed that your pool water is looking rather green lately, you're probably wondering what's causing the issue. The answer could lie in your pool filter. There are a number of reasons why your pool filter could be turning green, and in this article, we'll explore some of the most common culprits.

1. Algae

The most obvious cause of green pool water is algae. Algae is a common problem for pool owners and can cause your pool water to appear green, murky, or even black. Algae grows in areas where there is plenty of sunlight and warmth, such as near pool walls or in the pool's pump and filter system.

To determine if algae is the cause of your green pool water, you can do a simple "white bucket test". Fill a white bucket with your pool water, and if the water looks green in the bucket but clear in the pool, you likely have an algae problem. To fix an algae problem, you'll need to shock your pool and give it a good scrubbing.

2. pH Imbalance

Another cause of green pool water could be a pH imbalance. If your pool's pH is too high or too low, it can create an environment that is conducive to the growth of algae and other microorganisms. A pH test kit can help you determine if your pool's pH levels are off.

To correct a pH imbalance, you'll need to add chemicals to your pool to raise or lower the pH as needed. You may also need to adjust your pool's alkalinity and calcium levels as well.

3. Calcium Deposits

If you have hard water, it's possible that your green pool water is caused by calcium deposits. These deposits can build up in your filter system and create a greenish tint to your pool water.

To fix this issue, you'll need to clean your pool filter system thoroughly. You may also need to add a sequestering agent to your pool water to prevent calcium deposits from forming.

4. Copper and Iron

If your pool water has a green tint and your pH levels are balanced, the issue could be caused by copper or iron in your water. Copper and iron can enter your pool water through a variety of sources, including corroded pipes or metal pool equipment.

If copper or iron is to blame for your green pool water, you'll need to use a metal sequestering agent to remove the metals from your pool water. You should also consider replacing any corroded metal pool equipment.

5. Poor Circulation

Lastly, poor circulation in your pool could be contributing to your green pool water. If your pump or filter system isn't working properly, it can create stagnant areas in your pool where algae and other microorganisms can thrive.

To improve circulation in your pool, inspect your pump and filter system to ensure that everything is working properly. You may also want to consider adding additional circulation equipment, such as a pool skimmer or water jets.


As you can see, there are many reasons why your pool filter could be turning green. Identifying the cause of the problem is the first step in fixing it, and in most cases, a combination of chemical treatments and thorough cleaning is required. By taking preventative measures and maintaining your pool's filter system, you can prevent green pool water from becoming a major problem in the future.


Just tell us your requirements, we can do more than you can imagine.
Send your inquiry

Send your inquiry

Choose a different language
Current language:English