How to Test for Blue-Green Algae

Having a dam or water body on your property requires lots of maintenance. Whether you use it for leisure and your intricate floating lounge and trampoline system, or you maintain it for other organisms and species, keeping it safe, clean, and free from toxins takes work.

Blue-green algae is a common buzzword in the world of dam maintenance, but what is it? What harm can it do to you, your family, the fish in your dam, and other animals? And how do you take a water sample and test for it?

This article will answer all of these questions, including the big one: how to test for blue-green algae. Take a look below now to learn more about testing methods and ways to prevent this kind of algal bloom.

What is Blue-Green Algae?

Blue-green algae, or to use the scientific name, cyanobacteria, are a group of photosynthesising bacteria that, despite the name, are not actually true algae. As they get most of their energy from sunlight, this kind of bacteria is often referred to as algae and can be found in many residential and marine waters, including in lakes, ponds, rivers, and your dam at home!

Contrary to popular belief, not all cyanobacteria are harmful. In fact, as this bacteria can perform a process known as nitrogen fixing, which makes nitrogen available to other species, some cyanobacteria may even be thought of as good bacteria.

However, when the conditions are right, blue-green algae can multiply, causing what is known as algal blooms. A blue-green algae bloom will discolour the water, and the bacteria may produce toxins known as cyanotoxins.

Cyanotoxins not only impact water quality but can also have an adverse effect on humans and animals. Issues that they cause may include skin irritation and gastrointestinal problems to liver and nervous system effects.

Symptoms of Blue-Green Algae

Here are some of the symptoms of blue-green algal bloom:

• Water discolouration: This is the first and most obvious sign that you have an overpopulation of cyanobacteria in your dam. Water discolouration may be blue-green, brown, or red, depending on the type of cyanobacteria. 
• Floating scums: If you’ve begun noticing scums or mats on the surface of your dam or accumulating across the shoreline, this could be an indication of blue-green algae. Often these scums will resemble paint or pea soup.
• Unpleasant odour: Blue-green blooms may cause a foul or musty odour emanating from your lake, dam or pond.
• Dead fish and other wildlife: If you’ve noticed more and more aquatic life dying, this could indicate the presence of harmful bacteria.

It is essential to note that you cannot tell whether the cyanobacteria or algal bloom in your dam is actually harmful by just looking at it. This means it’s best to avoid entering the water if you suspect toxic bacteria and instead conduct a proper test.

Blue-Green Algae Test: Methods and Products

There are a few at-home testing methods that you can try before you purchase a proper blue-green algae test. These include the following.

The Jar Test

The jar test requires you to have a clear jar and rubber gloves. You should put on gloves and collect a sample of your dam water to about three-quarters full. Screw on the lid and leave the sample in the fridge overnight, undisturbed.

In the morning, you can check the sample and see where the algae has accumulated. If it is sitting at the bottom, it is less likely that the problem in your dam is blue-green algae. However, if there is a green ring at the top of the water surface, blue-green algae may be present.

In this method, it is important not to overfill samples as algae can produce gas and cause a pressure build-up in the jar.

The Stick Test

Another at-home testing method is the stick test. You’ll need rubber gloves again and a long and sturdy stick. Then, all you need to do is push the stick into the mat or scum formed on the water surface and slowly pull it out of the water.

If the stick comes out looking like it has been dipped in paint, then it is most likely blue algae in your dam. If the stick comes out with green strands and threads attached, then it is less likely blue-green algae but could be caused by filamentous algae.

In both these tests, safety is of the highest priority, which means that wearing gloves is essential. Toxic cyanobacteria can cause problems for you even with skin contact, so remember safety first.

Blue-Green Algae Test Kits

While your water can be tested with one of the above methods, we recommend only doing these tests to determine the likelihood of blue-green algae. Neither test gives you a definite answer, so you should always buy a proper test kit if you believe there may be toxic bacteria in your dam.

We stock blue-green algae test kits here at Love My Dam so that you can get a definitive answer and begin the treatment process immediately.

Preventative Measures for Blue-Green Algae

Preventing the growth of large numbers of algae means managing the factors that contribute to this growth in the first place. Some preventive measures you can take include the following.

• Reducing nutrient run-off: Both phosphorous and nitrogen help blue-green algae thrive, so we recommend implementing erosion control methods to prevent run-off into your water body. This could include vegetative buffers around the lake’s edge or using phosphorous-free fertilisers.
• Waste management: Proper disposal of pet and livestock waste can also help prevent any excess nutrient build-up in your water.
• Maintaining water quality: This might include using natural filters or probiotics to balance the ecosystem.
• Improving water circulation: Ensuring your water doesn’t become stagnant can help limit blue-green algae growth. Consider the installation of an aeration device.

Treating Blue-Green Algae

There are, thankfully, a number of ways that you can treat any bacterial growth in your water body after a positive test. Methods include the following.

• Mechanical removal: Physically raking and removing floating algae and algae mats is an effective method of treatment for small, localised blooms
• Aeration: Water circulation can prevent and treat algal blooms by increasing oxygen levels and stopping the growth of harmful bacteria.
• Biomanipulation: This might include introducing natural predators or competitors to blue-green algae, like zooplankton and herbivorous fish, into your dam.

If you’re struggling with blue-green algae growth in your water body, then don’t hesitate to reach out to the experts at Love My Dam. We’ve seen many water bodies with cyanobacterial overgrowth, so we have a range of effective treatment methods to help you out. If you’re wondering which kit is best for you, our team are always happy to give advice.

Final Thoughts

Blue-green algae isn’t always harmful, but when it is, it can wreak havoc on your dam. Testing for blue-green algae is the only way to know for sure if it is present in your dam. Our testing kits offer a definitive answer so that you can get started on treatment and implementing preventive measures.

Remember to reach out to us if you’re struggling with blue-green algae and don’t know where to start.