Skip to Content

How to Clear Green Pool Water Fast

How to Clear Green Pool Water Fast
This article may contain links from our partners. Please read our Disclaimer for more information.

The last thing you want to see when you go swimming is green pool water. It happens to the best of us though. A slight oversight or busy schedule, and pool maintenance gets put aside. 

Before you know it, you have an unsightly and unsafe pool to swim in (please don’t). Now rather than swimming, you’re trying to learn how to clean a green pool. 

Why Is My Pool Green?

Looking at your green pool, you may scratch your head and wonder why? What makes swimming pool water green you might ask. The answer is there are many things that cause pool water to become green. 

One of those reasons is algae. You know it’s a part of owning a pool, but why did it get so bad that your pool turned green? Continue reading to learn ways to fix green pool fast and safely. 

The reasons algae grows or overgrows, varies. It could be due to pool owner error, chemical imbalances, or even the weather. Here are a few of the most common reasons:

  • Imbalanced pH Levels – You don’t want a pH that’s too low because it will cause irritation to anyone in the water, especially the eyes. But, if the pH is too high, it causes skin irritation, and allows bacteria and algae growth, aka green pool water. 
  • Non-Working Filter – Check your pool filters often. If you don’t, they could easily clog up, which means the algae doesn’t filter out of the pool. Not only that, but you’ll have an overgrowth of bacteria, which means unsafe pool water, not to mention it’s abnormal green color.
  • Warm Weather – You want the weather to be warm for swimming, obviously, but drastic changes in the weather or humidity levels calls for more frequent and thorough cleanings as algae thrives in warm, humid temperatures.

Fortunately, there are ways to clear green pool water and not lose too much precious swimming time. Let’s check out how to clean a green pool fast.

6 Ways to Clear Green Pool Water

Pool water troubleshooting can be frustrating. Don’t worry though, when your pool water turns green and causes your swimming pools water to get disgusting we’re here to help! We’ll have your pool back to crystal clear water in no time.

Below we’ve outlined the first six things you need to do to help turn your not clear, cloudy pool into a beauty!

1. Check the Pool’s pH Levels

If the pool’s pH levels are too high, you’re more likely to have algae growth. Before you do anything, use a water test kit to test the pH levels. 

You can do a full-blown testing, checking all levels, or focus on the pH level for now. If the levels are too high, use your favorite method to lower pH levels using either sodium bisulfate or muriatic acid. 

Make sure you know the precautions to take and the amount needed (read the manufacturer’s instructions) before using either method. While you’re at it, you can check the chlorine levels, but typically if the pool water is green, you aren’t using enough chlorine.

2. Shock the Pool

Chances are if your pool has algae, its chlorine levels are low. Adding chlorine shock not only gets the chlorine levels where they need to be, but it also kills the algae – our main goal here.

Use a pool shock treatment you’re used to using or that you have carefully read the instructions and know how to use. The best shocks contain at least 70% available chlorine. Use your testing kit to make sure you have the right levels of chlorine in the pool after shocking.

In general, to kill algae, you need 30 ppm chlorine. If your pool is still green after shock, you may have to shock the pool twice, depending on the depth of algae. If after two shocks you still don’t notice a difference or the water isn’t completely clear, do it again. 

3. Scrub the Pool Walls

Once you’ve corrected the pool’s chemical levels, get in there with an algae brush and brush those side walls. This is one of the best methods when learning how to clean a green pool. 

Use your pool brush to get as much as you can , and get the floor too. Keep going until all stubborn algae has been removed from the pool. Consider brushing off any pool accessories or pool toys that may have been in the water too. If you have an inground pool, make sure you sanitize your pool ladder as well.

Don’t be afraid to put in some elbow grease here – you want to loosen all algae to get it out of your pool.

4. Run the Filter

This is the most time consuming part of fixing dirty pool water, but it requires the least amount of physical labor. 

Turn the pool filtration system on and let it run until the water turns clear. Let your filter system begin sanitizing, circulation helps move your pool chemicals around. This may not happen in a day or even two, it could take as long as five days. 

Keep checking back to see how the water looks. If you have light green pool water, keepin going and always keep a close eye on the pool filter. If it clogs up, make sure you clear it right away.

If you have a sand filter or DE filter, make sure you set it to backwash to remove the harmful water from the pool. 

5. Check the Water

Is the water still cloudy even after running the filter for a couple days? Use a flocculent to clear-up the cloudy pool water. Adding chemicals will help all leftover debris clump together. This makes it easier to get them out of the pool and keep it clean.

After using flocculant, vacuum the pool, removing all debris, leaving you with an algae-free pool.

6. Use an Algaecide

If you want to be extra sure you’ve removed all algae from the pool water, consider adding an algaecide. Not only will it kill off any remaining spores that you may not see, it helps your water remain clear moving forward, preventing further algae issues. 

When you combine an algaecide with other simple methods to prevent a green swimming pool, you’ll have a head start on preventing issues in the future.

If none of these steps work or your pool water is so dark green that nothing works, you may need to drain the pool. Use this as a last resort but if you can’t make changes it may be your best bet.

Tips for Preventing a Green Swimming Pool

Once you get rid of the green pool water, take the steps necessary to prevent a green swimming pool from happening again. Chances are you don’t want to go through these steps again, they aren’t for the faint of heart!

Use these tips to prevent algae from building up in your pool again:

  • Keep up With Pool Maintenance– A clean pool means a lower risk of algae growth. Don’t just skim your pool, scrub your pool walls and vacuum the floor at least weekly, especially if you notice light green pool water. This prevents the buildup of debris and algae and ensures you don’t end up with green pool water. 
  • Stay on Top of the Filters – Check your filter cartridge often. Is it clean residual residue and pool algae? Is it running properly? Water left to sit without filtering will easily build up algae. Check the filter for debris and clean it as often as necessary to ensure it’s running smoothly.
  • Keep the pH Levels Stable – Stay on top of your pool’s pH levels. Check them three times a week. Adjust the pH levels as necessary, keeping them within optimal range of 7.4 to 7.6.
  • Check Chlorine Levels – Always make sure your pool has the right amount of chlorine (not too much and not too little). Adjust accordingly to ensure your pool remains algae free.
  • Cover Your Pool – It’s a pain, but always covering your pool limits algae growth. It keeps debris out of the pool when no one is using it. Plus, it keeps the hot sun out of the pool, which can encourage algae growth if the pool water temperature changes quickly. 

Goodbye Green Pool!

If your greenish pool water taught you anything, it’s that you must stay on top of your pool maintenance. You can’t undo the past, but you can prevent green water moving forward.

After you put in the hard work to get rid of the green pool water, set up a regular maintenance routine to ensure you don’t have to go through this again. Having routine pool care ensures your pool safety and is an important part of owning a water oasis.

If you aren’t sure about your pool’s chemical levels, bring a sample to your local pool store to get the water tested so you know beyond a reasonable doubt what your pool water needs.