Pool algaecides are the fastest and most effective way to get rid of algae growing in a swimming pool. The first step towards killing the algae in your pool is to identify what type it is. Once you know whether it is green, blue-green, yellow/mustard or black algae you’re dealing with, you can then get the best pool algaecide to kill them.

We have identified ten tried and true swimming pool algaecides that work and compiled a quick guide on how to identify the best algae killer for your algae problem so you can restore your pool’s water to crystal clear and healthy. You can also incorporate algaecide in your weekly pool maintenance and use it when opening and closing your swimming pool to keep algae at bay.

How To Choose A Pool Algaecide – Buying Guide


To see the desired results, that is to get rid of the pool algae in your pool, you have to buy the right algaecide. Which top rated algaecide for pools will work best for you pool depends on what kind of algae is in your pool. It is also important to get a product that will work without damaging your pool water. Here is what to look for as you buy an algaecide for swimming pool. 

Type and Color of Algae

In order to buy the best algaecide for your swimming pool, you will need to know what type of algae you’re dealing with. There are three types of algae that invade swimming pools.

Green algae are the most common and most algaecides can eliminate them. Yellow or mustard algae are not as common but are hard to eliminate because they are chlorine resistant. Black algae are the hardest to get rid of, as they have a tough protective coating that chlorine and most regular algaecides can’t penetrate. If the infestation looks like red or pink slime, what your pool has is bacteria.

Once you’ve identified the type of bloom you want to eliminate, you can choose an algae killer for pools that works on all types of algae or find one that is designed for and reviewed as effective in eliminating the specific type of growth in your pool.

Type of Algaecide

Just as there are different types of algae, there are different types of algaecides based on the active ingredient.

Copper algaecides for pools are powerful and very effective at killing even severe green and yellow/mustard algae. If not used properly, copper algaecides can stain pools. Silver algaecides are effective at killing black algae.

Quat and polyquat algaecides are effective on various types of algae. Quat or quaternary ammonium compounds are actually detergents and they are notorious for foaming if they aren’t used properly. Polyquat or polymers are non-staining and non-foaming and come in 30 to 60 percent concentrations.

Products with poly(oxyethylene (dimethylamino) ethylene as the active ingredient are effective on small algae infestations. Sodium bromide control algae by enhancing the effectiveness of chlorine.


If you use an algaecide and it leads to foaming, you will be annoyed as this will mean extra work clearing the foam or having to wait for days for the foam to clear and the water to sparkle.

You can avoid this by choosing a non-foaming algaecide that won’t cause foaming. With such a treatment, the water will clean and clear quickly and you can take a dip in your pool shortly after applying the algae treatment. To prevent foaming, it is also important to apply the treatment as directed and avoid overdosing your pool.

With quat pool algaecides, quaternary ammonia can foam and cause suds. Polymer algaecides are non-foaming as are the best algaecides for pools we have reviewed here.


Once you apply a treatment, you want it to eliminate the existing algae and prevent regrowth. You don’t want to find a new infestation the following week. If you apply it when closing your pool for winter, you want it to protect your pool throughout the season.

Make sure you choose a treatment that will get rid of algae and keep it from returning by checking how long its active ingredient stays active and keep algae at bay. There are products that offer 90-day protection and there are some that guard your pool for as long as six months.

Pool Friendly

Whether you want the best algaecide for an above ground pool with a liner or have an in-ground pool, you want to be sure that the algaecide you use won’t damage your pool structure and components. If there is an ingredient that can damage pools, there will be cautionary text on the bottle or package. Be sure to read the writing that comes with your product and use it as directed.

You also need to make sure you choose an approved algaecide that does not contain hazardous ingredients that can harm swimmers. Most pool algaecides contain active ingredients that don’t harm swimmers and contain them in low concentrations such that it is safe to swim after an application. It is recommended to wait at least 15 minutes before using your pool after putting an algaecide in it.


While algaecides are not expensive, they are not a one-time purchase. Even after eliminating an algae bloom, you will want to apply a weekly dose for preventative maintenance. The cost and value are therefore important considerations. The economical option is one where a single treatment keeps algae at bay for a long time, one where one product purchase can last you a long time and one that improves water quality reducing the need for other chemicals.

Non-Staining and Stain Removing

An algae infestation messes up your pool by contaminating and discoloring it. The best pool algaecide is one that gets rid of the algae as well as the stains. It should turn your water from green to blue and crystal clear and leave the bottom and walls sparkling clean.

The algaecide itself should be non-staining. Copper-based algaecides can stain pools so choose a product that is formulated to be non-staining or has a low concentration of copper and apply it according to instructions.

Clarifying Algaecide

You definitely don’t want an algaecide that works but leaves you with a cloudy and foamy pool. You want one that makes the water crystal clear. Choose an algaecide for swimming pool that not only treats existing algae and prevents regrowth but also clarifies the water and leaves it bright and sparkling clean. You can tell whether a product is clarifying by checking its description and going through its pool algaecide reviews by pool owners.



Q: Why Should I Use A Non-foaming Algaecide?

A: An algaecide that foams up your pool water after doing its job is not one you want to use. Not only will the foam be unsightly, but it will also prevent you from using your swimming pool as you have to wait for the water to clear up. To prevent foaming and to be able to use your swimming pool minutes after applying an algaecide, you should use a non-foaming product and apply it according to the instructions that come with it.

Q: How Much Algaecide Should I Put In My Pool?

A: How much you should put in your pool will depend on the product you’re using. The user instructions your algaecide will come with will include the dosage to apply to eliminate the algae. The dosage is usually per 10,000 gallons of water. You can then calculate the quantity to add to your pool based on its size. Some manufacturers also provide a dosage for severe infestations, for weekly maintenance, and for when opening and closing your pool.

Q: When Should I Add Algaecide To My Pool?

A: You should add algaecide as soon as you notice an algae growth – a greenish yellow film at the bottom or sides of your pool. This will eliminate the algae before it can spread and colonize your swimming pool. For preventative maintenance, you should add it weekly after cleaning and balancing your pool.

Q: My Pool Still Looks Green After Adding Algaecide. What Should I Do?


First of all find out how long the algaecide you used takes to get rid of algae and restore your pool from green to crystal clear. It could be that the algaecide is still doing its job and you just need to be a little patient.

If it seems that the algaecide is not working, you can treat the pool again. For effectiveness, if you have stubborn algae, use a pool brush to brush the areas affected by algae growth before you add treatment. 

Start by adding chlorine, which is very effective at killing green algae, then add algaecide to get rid of the green color. It can take hours for your swimming pool to turn from green to the attractive clean and clear swimming pool blue.

Q: My Pool Looks Cloudy After Adding Algaecide. What Should I Do?


Your pool could be cloudy because your pool’s filters are not working properly or because there is insufficient chlorine in the water. The wrong pH balance also affects the performance of an algaecide.

What you should do first is clean the pool filters and make sure your water’s pH is within the proper range. Add chlorine until there is a sufficient level in your pool and then add a non-foaming algaecide according to the instructions. You might also have to vacuum out the dead algae to clear out the water. 

Globo Surf Overview

Wind, swimmers, rain and other things can introduce algae in swimming pools. They then lie low waiting for an opportunity to bloom with a vengeance. If the water balance is off even slightly, algae can appear almost instantaneously. You should get rid of them as soon as possible, as algae spread rapidly and make pool water unhealthy to swim in.

Adding the best pool algaecide for the type of algae growing in your pool is the most effective way to get rid of algae quickly. To prevent regrowth, keep your pool water clean and pool chemistry well balanced. You can also add a preventative algaecide weekly for maintenance of an algae free pool. 

More Pool Reviews:

How about you? Which algaecide for swimming pool is your go to? Have you used any of the algaecides in our list?  Let us know your thoughts and experiences in the comment box below!

Globo Surf Pool Algaecides Reviews

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Thank you for this article because without it I couldn't fix my pool. The pool turned green first but I thought that it's from the rain, however it turned out that it's some type of algae. Since I don't know how to fix it I turned to the internet for an advice and found this article.

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My name is David Hamburg. I am an avid water sports fan who enjoys paddle boarding, surfing, scuba diving, and kite surfing. Anything with a board or chance I can get in the water I love! I am such a big fan I decided to start this website to review all my favorite products and some others. Hope you enjoy!