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 is to identify what type it is. Once you know whether it’s green, yellow/mustard or black algae you’re dealing with, you can get the best pool algaecide to kill them.

Even if you don’t have an acute algae problem, an algaecide can help you prevent it. Incorporating it in your weekly pool maintenance routine and using it when opening and closing your swimming pool is a sure way to keep algae at bay.

To help you deal with this problem, we did an extensive research and identified tried-and-true swimming pool algaecides that will get the job done. We’ve also compiled a quick guide on how to find the best algaecides for green algae, so your pool water can be crystal clear and healthy all the time.

How To Choose A Pool Algaecide – Buying Guide


Which top-rated algaecide for pools will work best depends on what kind of algae is in your pool. It’s also important doesn’t do damage to the water or the pool. Take a quick look at what you should look for when buying an algaecide for the swimming pool.

Type and Color of Algae

To find the best pool algaecide you’ll 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, and are harder 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 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 their active ingredient.

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

Quat (quaternary ammonium) 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 Polyquaternium WSCP (polyoxyethylene(dimethyliminio)-ethylene) as the active ingredient are effective on small algae infestations. Finally, products with sodium bromide control the algae in your pool by enhancing the effectiveness of free chlorine.

Non-foaming Properties

An algaecide that leads to foaming is annoying – it means extra work clearing the foam manually, or having to wait for days for the foam to settle down and the water to sparkle. You can avoid this by choosing a non-foaming algaecide (a product that doesn’t cause foaming).

With such a treatment, the water will clean and clear quickly, allowing you to take a dip in your pool shortly after application. To prevent foaming, it’s also important to apply the product as instructed and avoid overdosing your pool.

Unfortunately, when using quat pool algaecides, quaternary ammonia can foam and cause suds. On the other hand, polymer algaecides are non-foaming making them perhaps the best pool algaecide if you want to avoid foam.

Durability and Frequency of Use

Once you apply an algae treatment, you expect it to eliminate the existing algae and prevent regrowth. Nobody wants to find a new infestation the following week. And if you apply it when closing your pool for winter, you want it to provide protection throughout the season.

For this reason, make sure you choose a treatment that will not only get rid of algae but also keep it from returning. Always be sure to check how long its active ingredient stays active and keeps algae at bay. Some products offer 90-day protection while others guard your pool for as long as six months.

Pool and Swim Friendly

Whether you want the best pool algaecide for above ground pools or your in-ground pool, you should make sure that the algaecide you use won’t damage the pool structure or its components. Some algaecide ingredients can potentially ruin the pool liner.

Luckily, if there is an ingredient that can damage your pool, there will be a cautionary text on the bottle or package. Because of this, be sure to read the writing that comes with the product and use it as instructed.

Additionally, you also need to make sure the formula is approved and doesn’t contain hazardous ingredients that can harm swimmers. Most active ingredients are perfectly safe for humans, and present in low concentrations so it’s usually safe to swim soon after an application. Still, it’s recommended that you always wait at least 15 minutes before using your pool.

Cost of Removing Algae

While algaecides are not expensive, they are not a one-time purchase. Even after eliminating an algae bloom, you should apply a weekly dose as a preventive measure. 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. It’s best if one product purchase can last for a long time, improving the water quality and reducing the need for other chemicals. Even if a product is initially more expensive, it might pay off in the long run if it lasts longer.

Stain Prevention and Removal

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 clear blue and leave the bottom and walls sparkling clean.

On top of this, the algaecide itself should be non-staining. Unfortunately, even though they are very efficient, copper-based products can sometimes stain pools. If you want to completely avoid stains, choose a product that is formulated to be non-staining or has a low concentration of copper, and apply it according to instructions.

You might also like: Best Pool Shock

Clarifying Effect

Nobody wants a product that kills algae but leaves you with a cloudy and foamy pool – it should make the water crystal clear. Choose an algaecide for swimming pool that not only treats existing algae and prevents regrowth but also clarifies the water. You can tell whether a product can do this by checking its description and going through the pool algaecide reviews left by pool owners.



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


As the name suggests, a non-foaming algaecide doesn’t leave any foam residue after application. Foam in the pool can be unsightly and keep you from using the pool until it clears up. If you want to avoid this altogether, you should go with a non-foaming product.

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


This depends on the product you’re using. Each product should come with instructions that specify the dosage required to eliminate the algae. For most products, this dosage is 1 pound per 10,000 gallons of water. Knowing this, you can calculate the exact quantity to add to your pool based on its size.

Q: When Should I Add Algaecide To My Pool?


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 in your pool before it can spread and colonize the entire swimming pool. For prevention, you should add it on a weekly basis (after cleaning and balancing your pool).

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


This can be caused by two things – either the algaecide hasn’t had enough time to work or it isn’t working properly. Find out how long the algaecide takes to get rid of algae – it could be that it’s still doing its job and you just need to be a little patient.

If it seems that it's 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.

Another thing you can do is add chlorine (very effective at killing green algae), and 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 the algae remover.

The first thing you should do 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 product according to the instructions. You might also have to vacuum out the dead algae to clear out the water.

Q: How Long After Adding Algaecide Can You Swim?


The recommended waiting time is 15 to 30 minutes. Although algaecides are perfectly safe for humans, it’s best that you let them spread properly so they can do their job. Additionally, copper-based products can change your hair color, so keep that in mind too.

Q: How Long Does It Take For Algaecide To Work?


Depends on the product itself as well as the type of algae. As we said, green algae are easiest to kill, and most products can do it within 12 to 24 hours. On the other hand, black algae are very persistent and can take up to 7 or more days to eliminate.

Q: Should I Use Algaecide Or Shock First?


You should use shock first. The ingredients in the shock interfere with algaecides and can significantly impact their performance. This is why you should add the shock, wait until chlorine levels drop to normal (under 4ppm) and then add algaecides to the water.

Q: How To Add Algaecide To Pool?


A great thing about algaecides is that most of them can be poured directly into the water. Still, make sure not to pour the whole bag at one spot – it’s better to evenly distribute it in several places in the swimming pool. Additionally, the pump will be responsible for dispersing it, so leave it running for at least 30 minutes after treatment.

Q: How To Get Rid Of Too Much Algaecide In Pool?


If you’ve accidentally added too much algaecide, there are a few things you can do. The first thing is to let it break down naturally, which can take days to over a week. This is especially annoying if the product is foaming.

Another thing you can do is add pool shock that will break it down immediately but will also render it useless. Finally, you can drain some of the pool water and then add fresh water to reduce algaecide concentration.

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 them quickly. To prevent regrowth, keep your pool water clean and pool chemistry well balanced. Including algaecides in your pool maintenance routine will guarantee a sparkling and algae-free pool.

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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!