While using natural pond care products can be the best way to prevent many common pond issues, pond chemicals, such as copper algaecide, are sometimes the best solution for ponds with severe algae issues. Captain® is an algaecide that can help with several types of algae and pond weeds, but it is crucial that you use this product correctly.

Before we talk about algaecide, it’s important to note that we sell many helpful pond products, including algaecides, herbicides and several all-natural products. Please do not confuse our chemicals with these all-natural products. Healthy Ponds natural products are not classified as algaecides or herbicides.


What Is Copper Algaecide?

There are a few different types of algaecide, but copper algaecide is one of the most common types you’ll find on the market. The active ingredient in these pond algae control products, copper sulfate, binds to algae and this prevents photosynthesis, which is how algae (and other plants) make glucose, which is their source of food. If they cannot produce glucose, and they die off.

You can purchase granular or liquid copper algaecide. Granular tends to sink quickly to the bottom of the pond, which reduces its effectiveness. Liquid copper algaecide will remain suspended in your pond water longer, which makes this a better choice.

However, the best option is to purchase a liquid chelated copper algaecide. Chelation is a process where the copper atoms essentially are “wrapped” with a coating, which helps them to remain at the surface of your pond longer and this can mitigate algae problems more quickly and safely than with non-chelated copper. Captain® is a chelated copper algaecide, which is why we recommend this product over other types of copper algaecides.


When Should You Use Copper Algaecide?

In general, there are many natural products that you can use to prevent algae from forming, but if your pond is heavily matted with filamentous algae or the color of your pond is pea soup green (which indicates planktonic algae), it’s probably time to consider using an algaecide. Captain® also can treat pitophora algae and muskgrass (Chara).

In some cases, if you have small amounts of filamentous algae or muskgrass, you can simply rake these algae out of the pond and begin treating the pond with natural pond products to prevent a resurgence of algae. You must be careful with muskgrass removal, as little bits of muskgrass left behind can quickly grow and become a problem again. But, again, if you have a stagnant pond or water that is smelly and covered with algae, a copper algaecide often is the best option to consider.


A Note About Koi & Trout

It is important to note that you cannot use copper algaecide in ponds stocked with koi or trout. If you are dealing with algae issues in ponds with these fish species, please contact us and we will recommend an alternative treatment plan, such as using Rush®.


How To Use Captain®

What to Wear – When applying copper algaecide to your pond, it is important to wear gloves, protective eyewear and protective clothing. Copper algaecide can cause skin irritation and damage your eyes, so taking precautions is essential. Once you’ve applied the algaecide, wash your gloves off and remove the protective clothing as soon as possible and wash these items separately from other items of clothing.

When to Apply – It is best to apply Captain® in bright, early morning sunshine. Captain® works best when the water temperature is at least 60 degrees. You also should not apply copper algaecide when the wind speed is greater than 15 mph. Spray drift management is an important part of the application process, so keep in mind that wind direction, wind speed and even the temperature and relative humidity can affect drift.

How To Apply – The first step you need to take before treatment is to ensure that you know which type of algae is in your pond. The application rates for Captain® vary based upon the type of algae in your pond. For instance, the dosage for planktonic or suspended algae differs from the dose you would use for filamentous algae and algae such as muskgrass (Chara).

Once you’ve identified the pond algae and determined the proper dosage, you can get started spraying the algae, and most people will use a hand pump sprayer to apply Captain® directly onto the algae, avoiding spraying any beneficial plants as much as possible.

With a copper algaecide, you only want to spray the liquid on ½ to 1/3 of the surface area of the pond, otherwise, you risk oxygen depletion in your water. If you have a pond stocked with fish, oxygen depletion leads to fish kills which can happen rapidly once the oxygen levels drop.

If your pond water temperature ranges between 65 to 85 degrees, only treat up to 1/3 of the surface area at one time. You can treat additional areas at intervals of at least 7 days. If your pond water is heavily matted, you may need to break apart these mats with a flat tool or high-pressure water before you treat with Captain®.

To learn more about application methods as well as proper dosages, you can access the label for Captain® at https://healthyponds.com/wp-content/uploads/2018/08/Captain_Label.pdf. Of course, if you have any questions about applying this product, feel free to contact us at any time.


When To Expect Algae Death

Typically, you will notice a change in the color of the algae within about 24 hours, which indicates that the algae have died off. Still, you do need to wait 7 days before treating other areas of the pond as too much copper algaecide will cause oxygen depletion in your pond water. The dead algae will eventually sink to the bottom of your pond.

Hopefully, this has answered a few of your questions about copper algaecide and Captain® in particular. At Healthy Ponds, we offer an assortment of pond maintenance products that can help you improve the water quality and clarity of your pond. In some cases, products other than Captain® might be the best fit and copper algaecides cannot be shipped to the following states:

  • Alaska
  • California
  • Connecticut
  • Maine
  • New York
  • New Jersey
  • Washington


If you live in any of these states and have issues with algae or pond weeds, please contact us at any time and we will help you find a pond algae solution for your pond. Whether you need copper algaecide or another pond water treatment, you can find everything you need at Healthy Ponds. We also offer free personalized water treatment plans for any size water feature at https://healthyponds.com/free-pond-plan/.

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Why Choose to Autoship?
  • Automatically re-order your favorite products on your schedule.
  • Easily change the products or shipping date for your upcoming Scheduled Orders.
  • Pause or cancel any time.