How to clean algae in an aquarium?

Cleaning algae from your aquarium is something you’ll inevitably have to do when you get into fishkeeping. Invasive plants like these are a natural occurrence in both aquariums and ponds. Therefore, their growth cannot be completely prevented.

That said, if you notice an algae bloom at the end of the nitrogen cycle, it is advisable to take action. Even though their appearance is natural, algae can be harmful to the aquarium and its inhabitants.

In this post, we will explore the possible alternatives for cleaning algae. We will see how to clean the aquarium to protect it from an invasion, but also how to deal with it effectively when you notice rapid growth.

You may also be interested in: our article explaining how to treat algae in a pond.

What problems are caused by the presence of algae in an aquarium?

In an aquarium, an algae bloom is generally a sign of a problem in the tank. Even if the phenomenon has less of an impact on the health of the aquarium, it will be just as noticeable. And for good reason: algae will certainly ruin your décor and make the aquarium look unsightly.

At the same time, a heavy presence of algae can also have harmful consequences for the living creatures in the tank. In other words, other plants, fish, and crustaceans could be affected by the algae bloom.

The high oxygen consumption of algae

Thus, an aquarium infested with algae can quickly harm your plants as well as your fish. This is due to the high oxygen consumption of algae during the night.

In the event of a bloom, your tank therefore dangerously loses oxygen. And this directly impacts its inhabitants.

Some algae are influenced by light

At the same time, there are also other species of algae whose consumption of carbon dioxide (CO2) is influenced by light. In other words, this greatly increases the pH of the water during the day (pH above 9).

For their survival, these particular algae extract CO2 from carbonate hardness (KH). This causes a significant drop in the amount of this element in the water, and pH instability.

The latter will drop sharply at night, then rise above 10 during the day. Eventually, such a situation will lead to the disappearance of all life in the aquarium.

Preventing the appearance of algae in the aquarium

Before dealing with the problem of treating algae, we can absolutely limit their spread. Of course, this starts with regular monitoring of the various parameters of the aquarium. And when we talk about monitoring, we are particularly referring to the various tests and periodic checks that must be carried out.

Taking algae nutrient sources into account

As we have seen before, the appearance of algae is completely normal. Simply put, the idea is to limit the amount of food available to the algae. To determine if the pond already contains the nutrients favorable to algae growth, we will start by testing the water parameters.

Nitrates

In themselves, nitrates are not as dangerous as ammonia and nitrites. That said, when you have a high concentration of nitrates, they can still be toxic.

The real problem is rather that they promote the growth of algae. Check that the nitrate level does not exceed 5-10 mg per liter.

Phosphates

Alongside nitrates, phosphates can potentially be the source of algae.

As they are also necessary for optimal plant growth, you will need to determine their concentration level and adapt the treatments according to the pond.

Check that the nitrate level does not exceed 0.1 mg per liter

Limit the phosphate and nitrate levels in the aquarium

Nitrate removal

To remove nitrates from the aquarium, the ideal approach is to opt for long-term biological filter equipment such as the JBL BioNitratEx.

For faster treatments, however, you should opt for filter media that can be placed in the filter, such as JBL NitratEX.

Phosphate removal

To remove phosphates from the aquarium while limiting the appearance of black and green algae, you can use a special filter media such as JBL PhosEX Ultra.

If you are considering a quick intervention, the JBL PhosEX Rapid liquid preparation will be more suitable.

How to limit algae in my entire aquarium?

In an aquarium, uncontrolled algae growth is very harmful to the creatures living in it. It is a sign of imbalance in your aquarium setup. Ideally, you should deal with it quickly or at least limit its growth.

Of course, there are several methods that can be used to clean and limit algae in an aquarium. In the event of an algae-infested tank and depending on the situation, you can therefore opt for one of the solutions proposed below.

Solution 1: clean your tank with algae eaters

One of the first methods is to make use of algae eaters. A very descriptive term, as they are shrimp, snails, or fish that are very fond of algae. In addition to limiting algae, algae eaters consume waste, as well as dead plants and animals.

Algae eaters will help you keep your equipment clean for as long as possible. Not only do they limit algae, but they also clean your tank and optimize the aquarium's ecological balance.

1. Snails

Snails are much more effective against green or brown algae. In this type of case, we recommend using snails called “Neritinas” for optimal results.

Simply put, these invertebrates use their scraping tongue to remove layers of algae. And this applies to glass, equipment, and aquarium décor alike.

However, it should be noted that Neritinas can cause an inconvenience. In this case, they can burrow deep into the substrate and cause groundcover plants to become uprooted. If this happens, you can opt for Clithon snails. These are smaller and less robust than Neritinas.

Recommendations:

• We recommend one snail per ten liters of aquarium volume.
• It is also important not to use chemical algae treatments in this type of tank: the snails will not survive them.

2. Japanica shrimp

In the case of shrimp, we recommend using them against filamentous algae. More specifically, we are talking about Japanica shrimp, which feed almost constantly. This notably helps limit the growth of algae layers.

Also known as Caridina multidentata or Caridina japonica, these shrimp can cause substrate fluctuations when their activity level reaches a high level.

You can also opt for Amano shrimp, which are just as effective. However, due to their large size, they are better suited for 60 cm aquariums.

Recommendation:

• Use one caridina per ten liters of aquarium volume

3. Fish Crossocheilus oblongus

The Crossocheilus oblongus is a Siamese algae-eating fish. Perfect for cleaning an algae-infested tank, this fish is quite large. Therefore, it is better suited to an aquarium with a volume greater than 200 liters.

Solution 2: use hydrogen peroxide to clean algae

Hydrogen peroxide (H2O2) can help control algae in a completely overrun aquarium, provided you strictly follow the manufacturer's instructions. This method should only be used if natural control methods have not worked.

For a pond, Biobooster+ is a different product based on microorganisms: please refer to its product sheet. Regardless of the product, use the lowest effective dose indicated on the label, as doing so could endanger life in your system.

After applying this treatment, some plants may temporarily change color. Do not worry; this does not mean there is a problem with your aquarium. They will return to their normal color after a few weeks.

To avoid harming the inhabitants of your tank, scrupulously follow the concentration and dose indicated on the product label to prevent a dangerous overdose in the aquarium.

This treatment is especially effective for treating green and blue-green algae. For the dosage, follow the product label.

Solution 3: use glutaraldehyde to clean algae

To treat red algae, green or blue-green algae in your aquarium system, it is recommended to use glutaraldehyde. The morning is the best time to use this solution, as it can consume a considerable amount of oxygen in the water depending on the dose.

Make sure your aquarium is well aerated if you plan to use the treatment over several days and at a high dose. You can use an aerator with a stone diffuser. For dosing, strictly follow the product label.

Cleaning algae in a specific area

Algae may only infest part of your aquarium. In this case, you do not need to treat the entire tank. Simply target the areas infested with algae and clean them. During this cleaning process, you will use a standard disposable 5 ml syringe and hydrogen peroxide or glutaraldehyde.

The syringe will allow you to extract the appropriate amount of liquid to treat algae in a specific corner. For this method to be effective, the current in the tank should be as low as possible. Repeat this treatment according to the label instructions to effectively clean the algae from the affected area.

Identifying algae in your aquarium

Each type of algae indicates a different imbalance. Recognizing them helps correct the right cause:

• Green algae: green fuzz on the glass, substrate, decorations, or plants. They often thrive due to lighting that is too intense or lasts too long.
• Filamentous algae: long green, sometimes brown or gray, strands attached to plants and decorations. They can be easily removed by hand and often indicate an excess of nutrients (nitrates, phosphates, iron).
• Brown algae (diatoms): a brown deposit that wipes off easily, common in new aquariums. It is linked to low or unsuitable lighting, or to silicates in the water.
• Cyanobacteria: a slimy blue-green film, often dotted with small bubbles. These are bacteria, not true algae: vacuum them out with a siphon and improve water circulation.
• Black algae and brush algae: small, dark, tightly attached clumps. See our articles on black algae and brush algae.

Lighting, water changes, and maintenance: the settings that matter

• Lighting duration: in a planted aquarium, about 8 hours a day is sufficient. A timer ensures consistency. Avoid direct sunlight, which adds to the lighting and heats the water.
• Water changes: regularly replace part of the water, for example 20 to 25% every one to two weeks, with water at the same temperature. Never change all the water at once.
• Population and food: too many fish or too much food means more nitrates and phosphates available for algae. Also reduce liquid fertilizer if algae persist.
• Manual maintenance: scrape the glass, brush the decorations and leaves, then immediately vacuum up the dislodged algae with a siphon. An old toothbrush attached to the end of the siphon hose allows you to scrub and vacuum at the same time.
• Unplanted aquarium: nitrate- and phosphate-removing resins can capture free nutrients.
• Massive proliferation: a few days of "blackout," with lights off and the aquarium covered, can slow down a major outbreak. Maintain good aeration during this period, then resume reasonable lighting.

Conclusion

The best solution to prevent algae proliferation in an aquarium is to adopt better habits. Change the water regularly, and have a good lighting and oxygen system.

If all this does not work, you are entitled to use treatments to clean your system.

You may also be interested in: our selection of oxygenating plants to keep a pond balanced.