If you have been keeping a planted aquarium for a while, you must have heard other hobbyists talk about liquid carbon. Liquid carbon dosing is a common method that many aquarium hobbyists use to control algae and support healthy plant growth. It's been around for years, and many aquarium brands, such as Aquavitals, now sell ready-made liquid carbon products for such a purpose.
If you are not sure about what liquid carbon dosing is or how to use it, let's learn about it first.
What Is Liquid Carbon?
Many aquarium companies sell liquid carbon as a plant supplement. It is usually known as liquid CO2. However, that is not actually what it is. Liquid carbon helps plants grow, but not by adding carbon dioxide to the water. Instead, its main job is to slow down or control algae growth. When there is less algae in the aquarium competing for light, nutrients, and carbon dioxide, plants get better access to everything they need to grow strong and healthy.
Most liquid carbon products contain glutaraldehyde or similar compounds that help reduce algae growth.
Check out How to Prevent Algae Naturally Without Harsh Chemicals?
Is Liquid Carbon Safe For Fish and Shrimp?
Yes, it is generally safe for fish, shrimp, and snails, only when it is used according to the manufacturer's recommended dosage. Most commercial liquid carbon products are designed to be safe for the aquarium livestock when used correctly. However, liquid carbon products mostly contain glutaraldehyde or similar compounds, which can become harmful if you overdose. And, in case you are using more than the recommended amount, it can stress or injure fish, shrimp, snails, and various sensitive plants. If you want to use liquid carbon safely:
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Follow the dosing instructions.
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Start with the recommended dose, especially when your aquarium has fish or shrimp.
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Don't overdose or spot-treat large areas of algae at once.
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Check your fish after dosing for any signs of stress, such as unusual activity, swimming, or gasping on the surface.
Is Activated Carbon The Same As Liquid Carbon?
No. Their names are the same, but activated carbon and liquid carbon are completely different products with different jobs. Activated carbon is a filter medium. It removes odors, tannins, medications, and other unwanted chemicals from the water. It helps keep the aquarium clean. However, liquid carbon is a plant additive. It is mainly used to help control algae, which allows aquarium plants to grow better. It is not used for filtration.
Can Liquid Carbon Replace a Pressurized CO2 System?
No. Liquid carbon cannot replace a pressurized CO2 system. As these are not sold as a carbon source for plants, they do not provide the same amount of carbon dioxide (CO2) that a pressurized CO2 system can.
That's why it cannot match the plant growth and performance of CO2 injection. Many aquarium plants grow naturally in places where there is a huge carbon dioxide. In a planted aquarium, adding CO2 can help these plants grow faster and healthier, with brighter colors.
Liquid carbon can be enough for some low-tech planted tanks, but it is usually not enough for high-end aquariums with demanding plants. Some plants, such as Vallisneria, are damaged by some liquid carbon products.
If you want optimal plant growth, especially in a high-light aquarium, a pressurized CO2 system can be the right choice. One of the signs of healthy plant growth is pearling. It is where plants release tiny oxygen bubbles during photosynthesis.
You may want to know Liquid Carbon vs CO2 in Planted Tanks: Which Is Better for Indian Aquariums?
How Can You Use Liquid Carbon in A Planted Aquarium?
Liquid carbon can be used to control algae, usually black beard algae (BBA). When there is less algae competing for light and nutrients, aquarium plants can grow stronger and healthier. If you want to use liquid carbon:
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You can measure the right amount using the measuring cap or cup that comes with the product.
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Add it to your aquarium depending on the manufacturer's instructions.
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Avoid using more than the recommended dose. Too much liquid carbon can harm fish, shrimp, and sensitive plants.
Here are 5 Signs That Your Fish Might Need Supplements or Medications.
How Often Should You Add Liquid Carbon?
The frequency of adding liquid carbon depends on the product and your aquarium. You need to follow the dosage instructions on the label to avoid causing harm to your fish or plants. In most aquariums, liquid carbon is added every 2-3 days or daily in heavily planted tanks or aquariums with strong lighting. Do not ever add more than the recommended amount.
Which Plants Are Sensitive to Liquid Carbon?
Some aquarium plants are sensitive to liquid carbon. Plants such as Vallisneria, Hornwort, Elodea (Anacharis), and some mosses can melt or be damaged after repeated dosing. If you keep these plants, you need to start with a lower dose and check them closely for any signs of stress.
Can You Use Liquid Carbon to Treat Algae?
Yes. Liquid carbon is used to spot-treat black beard algae (BBA). To do it:
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Turn off the filter and any pumps so that the water can remain still.
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Use a small pipette or syringe to apply a small amount of liquid carbon onto the algae.
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Turn the filter and pumps back on after applying it.
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Keep an eye on algae over the next 7 days. If the treatment is working, the algae will change color before they die.
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If needed, you can repeat the treatment on small areas once every week until the algae is gone.
Use Liquid Carbon Dosing Safely.
Liquid carbon is a useful addition to the planted aquariums when used correctly. It can improve water quality in the planted aquarium.
It can also help control algae and can support healthy plant growth. However, it cannot replace a pressurized CO2 system. Always follow the recommended dosage, check your fish and plants, and avoid overdosing.