Nobody wants algae in their tank. Especially not black beard algae, which are a nightmare. Why? Because it’s really hard to get rid of this fuzzy mess.
But it is possible to win this fight against black beard algae. I wrote a detailed strategy to help you fight black beard algae. Read here my step-by-step plan for black beard algae removal!
What are black beard algae and what do they look like?
Black beard algae can be found in various forms:
- Spots of fuzz on your decor and leaves
- Short hairs on leaf edges and decor
- Grey filaments (not to be confused with thread algae)
- Dark layer on leaves, a bit like brown algae but much rougher…
Black beard algae in an aquarium can be a real plague. They are not only difficult to remove, but they also grow in groups, on almost everything! Before you know it, you find black beard algae everywhere (except on your slow-growing plants), even on your equipment and beautiful decor.
So, the key question is, why are there black beard algae in your aquarium?
What are black beard algae causes?
There’s not always a single cause; in fact, black beard algae often arise from a combination of factors. However, the CO2 levels always play a role:
- Bad water circulation: CO2 (and other nutrients) cannot reach all your plants, particularly in specific areas of your tank
- CO2 deficiency: you simply don’t add enough CO2 to your aquarium
- Unstable CO2 levels: fluctuating CO2 levels create a perfect biotope for black beard algae.
Now, how to fight black beard algae? It starts with prevention. Here is how.
How to prevent black beard algae in your aquarium?
If you want to prevent the growth of black beard algae, I recommend you tackle one problem at a time by following the guide below.
Step 1: Take the Golden Triangle into account
I know, theory can be boring but sometimes, it can really help you understand how things work in your aquarium. Have you heard of the Golden Triangle? It shows the relationship between light, CO2, and nutrients. The principle is simple: light is on top and allows your plants to grow via photosynthesis. So, if your tank is strongly lit, your plants grow faster and they need more CO2 and nutrients. Both are at the basis of the Golden Triangle.
So, keep an eye on this balance! Example: you love having a strongly illuminated aquarium where the bright colors of your plants come into their own. However, you add too little fertilizer. What happens? You get a situation in which your plants first thrive and then suddenly stop growing, because there’s no more food. Before you know it, your plants get weak and algae take the upper hand!
Use the Estimative Index (or my All-in-One) to add nutrients. And follow the tips below to safely increase your CO2 levels.
Step 2: Avoid CO2 deficiency, make sure you add enough CO2
If your aquarium suffers from CO2 deficiency, follow these steps to increase the CO2 level in your aquarium safely.
- Open the needle valve of your CO2 system a tiny little more (turn a few millimeters) to increase the CO2 supply. Do this in really small steps, with a maximum of one change per week, because you really want to avoid big fluctuations
- Carefully watch the behavior of your fish for several days and several times per day
- If your fish don’t show any weird behavior, then you can increase the CO2 supply again as described in the first step
- Meanwhile, use a good drop checker and aim at a lime green color for a good CO2 level
When should you stop increasing the CO2 supply? If you notice that your fish start gasping for air at the surface, acting nervous or becoming sluggish, then CO2 levels are probably too high and you should decrease them a little.
When you notice that your plants do well and black beard algae stop growing, you can also choose to stop increasing the CO2 supply.
Step 3: Decrease the light intensity
Remember the Golden Triangle. More lighting means that your plants need more CO2 and more fertilizer. Adding fertilizer is easy (for example with my All-in-One) but adding the right amount of CO2 is more challenging. And algae are right around the corner.
That’s why it’s a good idea to decrease the intensity of your lighting. You go for the inverse reaction: your plants will grow a bit more slowly (but still in a healthy way) and therefore, they will need less CO2 and fertilizer. As you’ve already increased the CO2 supply in step 2 and you are now decreasing the CO2 demand, the CO2 deficiency is quietly but surely going to disappear. Your plants will grow better and black beard algae will decline.
There are several ways to dim your aquarium lights. You can remove the reflector, hang your lamps further away from the tank, install a dimmer, use fewer lights or even add some floating plants. These are all ways to decrease the light intensity. Combine this with a lighting duration of maximum 8 hours per day. As you’ll notice, it will get much easier to keep everything in balance; your plants will only grow a little more slowly.
Step 4: Stabilize the CO2 levels
As I said at the beginning of the article, unstable CO2 causes the growth of black beard algae.
But what causes unstable CO2? Well, for example, it happens if you only start adding CO2 when the lights go on. At that moment, there’s no dissolved CO2 in the water yet, but your plants are already beginning their photosynthesis. Consequence? Your CO2 is not yet available for your plants (= CO2 deficiency), only later (= CO2 content increases in the course of hours). So, you get an unstable CO2 level, especially if you compare the first and the last hours of the lighting period.
Take the following steps to stabilize your CO2:
- Get rid of the scum at the water surface. This layer gets in the way of gaseous exchanges between water and ambient air and therefore causes the accumulation of CO2 in your aquarium. You can use a surface skimmer.
- Improve gaseous exchanges by creating nice “waves” on the surface. You can do so by placing your filter outlet just below the water surface.
- Start adding CO2 at least 1 hour before the lights go on, so that your CO2 has time to dissolve in the water before photosynthesis begins.
- Check the water pH during the whole lighting period. The pH value should be quite stable.
This method provides a much more stable pH and therefore much less fluctuation of the CO2 level.
Step 5: Optimize the water circulation
Optimizing water circulation in your aquarium is a permanent process. It’s not labor-intensive, but it has to be part of your routine. What are the causes of bad water circulation?
- Weak filter
- Poorly maintained filter which gets clogged
- Bad filter outlet
- Bad position of the filter inlet and outlet
A bad water circulation causes a CO2 deficiency in areas that are difficult to access. So, how to check whether your water circulation is good?
- All plants move a little with the flow
- You don’t have any “dead spots”, those areas where plants grow much less or where you see more algae
- There’s no waste floating around in your aquarium
So, regular maintenance of your filter is crucial, as well as testing various positions of your filter inlet and outlet. Also, check regularly whether your water circulation is good and all plants nicely move a little.
How to remove black beard algae from your aquarium?
OK, now that you’ve taken all necessary measures to prevent black beard algae in your aquarium, it’s time to remove black beard algae that are already there.
Black beard algae removal by hand
Unfortunately, it’s no fun… Black beard algae tend to cling very strongly to decor and plants, so it’s almost impossible to remove everything by hand if you have a black beard algae invasion.
- Black beard algae on the glass: use a razor blade
- Black beard algae on decor: use an old toothbrush or small and sharp tweezers
- Black beard algae on aquarium plants: remove badly affected leaves, the plant will make new ones
I also recommend using a liquid source of carbon to attack and weaken black beard algae, very helpful for manual black beard algae removal.
Black beard algae removal using a liquid source of carbon
These products contain “glutaraldehyde”, a substance that is dreaded by algae.
- Fill a syringe with liquid carbon (stick to the indicated amount!)
- Apply directly on black beard algae
- Once the black beard algae are discolored (meaning they died off — after about two weeks), they are soft enough to be removed easily
Further, keep everything under control by removing affected leaves regularly. For a given plant, never remove all affected leaves at once. Give your plant time to recover, by removing no more than a couple of leaves every week.
Black beard algae removal by black beard algae eaters
You can go a step further by calling in a support team: fish that eat black beard algae. Yes, they do exist! Siamese Algae Eaters and Amano Shrimps can help if the black beard algae are already weakened (e.g., after the liquid carbon treatment).
In short, black beard algae eaters are a perfect addition to your tank, as long as they are compatible with the other aquarium inhabitants of course! By the way, you can read more about aquarium algae eaters here.
Conclusion
Black beard algae in your aquarium are really annoying, but no drama. And it doesn’t mean the end of your hobby. There’s always hope. You wanna fight those black beard algae?
- Take the necessary measures in terms of CO2 and the Golden Triangle
- Reduce lighting, add more CO2 and improve water circulation
- Use a liquid source of carbon to weaken black beard algae
- Manually remove as much black beard algae as you can
- Optionally add shrimp and fish that eat black beard algae
Good luck!