A Guide to Using Algaecide in Your Pool

Written by Michael Dean
March 27, 2024

algaecide being poured into a swimming pool

Algaecide is an excellent tool that pool owners use to kill off algae in pool water. While you shouldn’t use it as a replacement for chlorine, algaecide is an effective option if you need that extra power to kill off an algae infestation. Whether you are a new pool owner or simply want to brush up on your algaecide knowledge, if you understand how to use it, you will be able to use it as effectively as possible.

In this article, I provide a full breakdown of what algaecide is, list the different types, and explain how to utilize it effectively. Let’s get into it.

Main Takeaways

  • Algaecide has a copper base that attacks algae and stunts their growth.
  • There are different types of algaecide: quat pool algaecide, metallic pool algaecide, polymer pool algaecide, and sodium bromide.
  • While algaecide is formulated specifically to get rid of algae in a pool, chlorine is still the most effective solution to killing algae.
  • You should add algaecide to your pool every week as a secondary sanitization option.

What Is Algaecide, and How Does It Work?

Algaecide is not a quick solution to completely get rid of algae in your pool. It is more often used as a preventative measure rather than a reactive treatment. Algaecide is a chemical that not only kills algae but also stunts their growth in your pool.

Most of the algaecides on the market contain a copper base, usually derived from copper sulfate. These chemical compounds utilize metal as its primary atom, which helps attack algae much more effectively.

So, how exactly does algaecide work? Simply put, algaecide discourages the typical cellular growth process of algae. By blocking cell division or energy transfer, this chemical limits the creation of newer cell proteins, which help algae survive.

When you use algaecides, please ensure you wear the appropriate personal protective equipment, which will be recommended on the product label. Generally, I recommend at least wearing rubber gloves and goggles.

Different Types of Pool Algaecide

You can choose from a few different types of algaecides. Below, I will list the best pool algaecides on the market in each type and when to use them.

Quat Pool Algaecides

A Quat pool algaecide, also known as a Quaternary Ammonium compound, is the most budget-friendly type of algaecide. It works as a microbial disinfectant. Quat algaecides work by attaching themselves to negatively charged algae cells. And once bonded with the algae, they disintegrate the outer protective membrane. Finally, by dissolving the outer layer, the chlorine is then able to kill the cell’s nucleus.

Remember that since they are basically a detergent, Quat pool algaecides can cause some foaming when overused. But with that said, if you want the most bang for your buck, this is an excellent algaecide option and comes in both 50% and 10% concentrations. You can pick some up from Clorox for pretty cheap.

Clorox Pool&Spa Green Algae Eliminator2

Here's a Clorox algaecide that works well in every pool I've used it in.

View on Amazon View on Walmart
I may earn a commission if you make a purchase, at zero additional cost to you. This in no way impacts my research process or opinions.

Metallic Pool Algaecides

This type of pool algaecide holds copper ions, a trusted solution in water treatment for thousands of years. To minimize potential staining from overuse, the copper is bonded with amino acids. Much like the other algaecides on the list, the positively charged metal ions attach themselves to the algae, invade the algae walls, poison the enzymes, and attack the nucleus.

Metallic pool algaecides are an ideal option for black algae and are also useful against green and yellow algae. Most average copper algaecides run between 7% and 9% copper strength or concentration. Below is a good option from In the Swim.

In The Swim Super Pool Algaecide

In The Swim makes great pool maintenance products, and this algaecide works very well if you need a metallic pool algaecide.

View on Amazon View on Walmart
I may earn a commission if you make a purchase, at zero additional cost to you. This in no way impacts my research process or opinions.

Polymer Pool Algaecides

Polymer pool algaecides, or Poly-Quat compounds, are versatile algaecide options because they are both non-staining and non-foaming. These positively charged polymers spread over the algae cell’s surface and surround the cell for the kill – two times faster than Quat algaecides.

Poly-Quats are much longer-lasting and more effective than regular Quat algaecides but are also more costly. These algaecides usually get sold in 60% and 30% strengths or concentrations. If you are someone on a budget, you may want to research other options. But this multi-season algaecide provides a consistent cleaning no matter what time of year it is. I recommend the Rx Clear algaecide.

Rx Clear Algaecide 60 Plus

Rx Clear makes a strong Poly-Quat algaecide that is more expensive, but also more effective.

View on Amazon View on Walmart
I may earn a commission if you make a purchase, at zero additional cost to you. This in no way impacts my research process or opinions.

Sodium Bromide

Sodium Bromide is not an algaecide, but when mixed with granular chlorine, it makes for the perfect catalyst to fix your algae-filled pool. The pool shock plays a pivotal role in converting the bromides into an algae killer.

Bromides are not usually used to prevent or control algae like algaecides, but it is used to deal with more severe cases of algae infestations in the pool. It works effectively against yellow or green algae that are not responding to a chlorine shock. No Mor Problems makes a good option.

United Chemical No Mor Problems Swimming Pool Algaecide

United Chemical makes an effective sodium bromide option for tough algae outbreaks. It's also used to prevent algae.

View on Amazon View on Walmart
I may earn a commission if you make a purchase, at zero additional cost to you. This in no way impacts my research process or opinions.

Different Types of Algae

Algae can come in many different forms. Below are the main types of algae that will make a home in your swimming pool:

  • Green algae: Also known as blue-green algae, this is the most common type and needs sunlight, warmth, and water to survive.
  • Black algae: A strain of blue-green algae attracted to plaster pools and contains a thicker cap that offers extra protection against algaecides.
  • Yellow algae: This is a different variation of green algae, which is chlorine resistant and can still live without the help of sunlight.
  • Red algae: This type of algae is associated with a different bacteria genus and can survive without sunlight.

Why Chlorine Is the Best Weapon Against Algae

Although algaecide is specifically designed to kill algaecide, it is not necessarily the most effective solution. Chlorine is much more successful at getting the job done, even if your walls are extra slimy and your walls are cloudy. According to the Missouri Department of Health, chlorine reacts with water to produce a sanitizing species, hypochlorous acid, to kill algae.

Chlorine’s differentiating factor is its ability to oxidize single-celled algae and bacteria. When chlorine is implemented, it trades electrons with the algae. When this exchange happens, the cell walls of the algae get ruptured. As soon as the process is complete, the algae cells are deprived of the necessary nutrients. Over time, consistent use of chlorine will limit the algae replication and growth process.

Much of the battle here is ensuring you maintain an ideal pool water chemistry with chlorine, bromine, or biguanide. Combined with a balanced pH level, this will be an effective protector against algae growth in your pool.

When to Use Algaecide

Algaecides serve as a secondary sanitization option for your maintenance system and prevent the ugly sight of algae in the pool. The key word here is prevention. So, don’t wait till it’s too late! Here’s everything you need to know about when to use algaecide:

  • After shocking: I recommend adding algaecide to your pool after each shock treatment session, so that would be weekly. But when you do, make sure to do so after the chlorine levels are under 5 ppm. If you’re trying to clear a green pool with shock and algaecide and both don’t seem to be working, check out my article on what to do next when shock and algaecide aren’t enough.
  • After cleaning: To ensure the best performance from your algaecide, clean the pool beforehand. Debris, leaves, and other particles tend to consume algaecide, which limits it from doing its job. So, add algaecide after you have brushed, vacuumed, and skimmed the surface.
  • After balancing the pool chemistry: Furthermore, the pH balance of the pool should also be somewhere near the middle. It would help if you avoided higher pH, calcium hardness levels, or alkalinity before adding algaecide to the water.
  • To treat other issues: Algaecide can also be a good treatment for pool foam.
  • During the day: I recommend adding algaecide during the day rather than at night, as algae grow and bloom under the sun.

As a top tip: After adding algaecide, make sure to run your pool pump and filter to evenly distribute the algaecide throughout the pool.

Get My Free Pool Care Checklist

Download my free, printable pool maintenance checklist to help you accomplish regular pool care tasks for any type of swimming pool.

Something went wrong. Please check your entries and try again.

How to Use Algaecide in Your Pool

Here’s my step-by-step process on how to use algaecide in your pool.

Step One: Clean the Pool

First things first, clean the pool. Brush the walls, vacuum the debris, and skim the surface.

Step Two: Balance the pH and Chlorine

Test the pH of your pool, which should be between 7.2 and 7.6. Your free chlorine levels should lie between 1 and 3 ppm. Adjust as necessary.

Step Three: Calculate the Dosage

Determine how much algaecide to add to your pool by following the manufacturer’s instructions. The dosage will be based on how many gallons of water your pool holds.

Step Four: Add the Algaecide

Now it’s time to put on some gloves and goggles! Once your hands and eyes are protected, pour the calculated amount of algaecide into the pool.

Step Five: Circulate the Water

Turn on your pump and filter, allowing the algaecide to circulate throughout your pool. Wait around 15 to 30 minutes before you jump back into the pool.

Say Goodbye to Algae!

One of the most annoying things pool owners have to deal with is algae. But armed with some chlorine and a dose of algaecide, your pool will be well on its way to becoming sparkly clean once again! While algaecide can be an effective solution to fight a green pool, keep in mind that it should be more used as a preventative. After all, prevention is the best medicine.

Questions? Feel free to shoot me a message, and I’ll be glad to help.

Scroll to Top