How to get rid of algae in large pond? Let’s find out!

If you have a pond, it is important to maintain it in terms of how it looks, the health of your fish, and the pond’s ecology. Algae are something that could bother you if you’re maintaining a large pond. While most of the time, algae are not that harmful, there are some toxic strains, which can quickly take over the pond in no time. However, by taking appropriate steps, it is possible to eradicate algae from your pond.

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How to get rid of algae in a large pond?

Pond algae is a common problem and once it has taken over your pond, it might seem like a challenging task to completely get rid of it. Of course, you can find algaecides and copper-based chemicals on the market; however, they only give short-term results. Moreover, they aren’t eco-friendly and fail to address the root of the problem.

The best approach to getting rid of pond algae is to work with nature and address the cause of the problem in order to enhance the overall water quality of the pond and create a balanced ecosystem. While this approach takes a longer time to get rid of algae in your pond, the result will last!

Before I delve into the details, let’s briefly discuss algae.

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What should you know about algae?

Algae is a collective term to address a large group of plants that range from small microalgae to huge macroalgae. As far as ponds are concerned, free-floating single-celled algae that are planktonic, colony mat algae (filamentous), or complex-branched algae are generally found. Blue-green algae or cyanobacteria are also present in some cases.

Contrary to popular opinion, most algae are not inherently bad. In fact, if your pond is totally devoid of algae, it isn’t ecologically balanced. Note that fish cannot survive in swimming pools!

Algae are found across the world in every other kind of ecosystem; they actually form the basis for the aquatic food web. Your focus should be to control only the algae that are causing excessive nuisance. It’s never a good idea to eradicate all types of algae if you wish to maintain an ecologically balanced pond.

Planktonic and filamentous algae are unsightly issues and often result in oxygen depletion problems, eventually killing fish in the pond. In addition, blue-green algae can be toxic to both animals and people. No matter what type of algae you find in your pond, excessive growth is considered undesirable.

You should be aware of the fact that the same conditions that escalate the growth of filamentous and planktonic algae encourage the growth of blue-green algae as well. These conditions include stagnant water, high nutrient levels (phosphorus and nitrogen), and excessive sunlight. Hence, the solutions are normally the same for any type of algae issue.

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Pond Algae Solutions

As mentioned earlier, some algae are necessary to maintain an aquatic ecosystem. However, what kind of algae and how much of it depends on the kind of pond you have. You should consider your expectations and personal uses for the pond. When it comes to natural ponds or fish ponds, a lot of algae growth is probably acceptable whereas this is not the case for decorative ponds and swimming ponds. 

The best method to prevent any sort of algae problem is to stop it even before it starts. To begin with, you should eliminate the conditions that actually promote excessive algae growth in your pond.

Remember that algae problems often stem from a surplus of nutrients in the pond. These nutrients may come from different sources, including grass clippings, lawn fertilizers, decaying leaves, leaking septic systems, and others. Controlling these sources of nutrients seems like a great place to start.

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Preventive Measures

Now, let’s take a look at some significant preventative measures you can take.

Build a pond with algae defense in mind

If you choose to build a new pond in your backyard or on your farmland, try creating a design with built-in algae protection. It’s the shoreline depth you should focus on.

Oftentimes, we see ponds built on a gradient; they become shallower as they draw closer to the shore. Well, this shape seems to encourage plant growth along the shore of the pond, which eventually encourages algae overgrowth.

What you can do is give your shoreline a 2-to-3-feet depth.

By doing so, you’re making photosynthesis on the floor of the pond more difficult, thereby discouraging unwanted growth. Planting desired plants all along the edges of the pond will discourage erosion, thereby maintaining your shoreline. If you intend to use the water in your pond to keep livestock hydrated, you can pump water elsewhere instead of allowing livestock to come to the pond for a drink.

Use a tarp to interrupt photosynthesis

Well, if you’ve already built your pond but are concerned about shallow waters, don’t worry. It is possible to still discourage photosynthesis on the floor of the pond. To do that, you need a large sheet of grey or black plastic and a few stakes.

Make several small holes in the tarp to allow oxygen to escape. You can then stick the tarp to the floor of your pond so that it doesn’t get pushed around or float to the surface.

Stock the pond with algae eaters

Adding voracious algae eaters to your pond will help control pond algae. For instance, try adding Asian triploid grass carp to maintain algae levels in your pond naturally.

If it’s just a minor algae problem, adding five fish per acre of pond is a good bet. For moderate algae problems, add 10 to 15 fish per acre. For severe and recurrent algae problems, you may have to add over 15 fish per acre of pond.

Other preventive measures include:

  •  Don’t overfeed the fish.
  • When mowing and trimming, make sure lawn clippings don’t get to the pond.
  • Make sure you have a well-maintained “filter strip” of natural vegetation along the edges of the pond.
  • Don’t overuse lawn fertilizers near the pond.
  • Control the waterfowl (like geese) from utilizing the pond much.
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How can you control pond algae through the year?

If the algae problem in your pond is already knee-deep and you’re on the lookout for a way to control it, with the following tips and tools, you can manage algae throughout the year.

Skim away or rake the early blooms

It’s in the early spring that the plants start to bloom. At this time, you’ll have to manage any early blooms that show up in your pond. A great tool to clear these early blooms is an algae rake. It effectively breaks up and gets rid of the early algae blooms.

Algae skimmers are also a great tool to keep the pond algae under control. You can use skimmers for larger ponds.

Add aeration

If you want to discourage the overproduction of blooms throughout the year, installing a pond aerator helps. All ponds contain phosphate and nitrogen levels controlled by dissolved oxygen. While dissolved oxygen is an integral part of fish health and decomposition, when there is more or less of it, the pond tends to lose its natural balance.

When there are low levels of dissolved oxygen, phosphate and nitrogen levels increase, eventually creating an ideal environment for the overproduction of algal blooms. If you introduce an aerator, you can ensure that the other organisms in the pond become better equipped to feed on the algal blooms and ultimately, maintain equilibrium. 

Try an algaecide

The methods stated above may take some time, and if your pond is in a really bad state, your next step should probably be to add an algaecide to your pond. Algaecides are capable of clearing up even the worst algae-ridden ponds.



How to get rid of algae in a large pond? I’m pretty sure you would’ve had a good knowledge of the various methods you could try to maintain your pond without the algae problem.

It’s obvious that following the various prevention measures is the best approach in this regard. However, if you’ve already faced the pond algae issue, you can rake the early blooms in the spring, introduce an aerator in your pond, or, as a last resort, add an algaecide.

Having said that, a little algae growth in your pond is essential to maintaining the ecosystem, especially if there are fish. I hope the information in this article helps you manage or get rid of algae in your pond.

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Oliver Wright
Oliver Wright

I hope you enjoy reading some of the content and ideas from this site, I tend to share articles and product reviews on a daily basis, so be rest assured… you won’t run out of things to read!

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