Best Activated Carbon For Media Reactors

This article will outline the best-activated carbon on the market today that can be used in a media reactor.

There are many different types of filter media available for use on saltwater tanks. They all have a specific purpose.

Activated Carbon is one of the more commonly used filter media and it can be used in different ways.

Using a media reactor with carbon inside is a very popular and effective way to achieve and maintain healthy water in your tank.

But not all carbon is the same. Some are better than others.

If you are looking to run quality carbon filter media inside a reactor, you need to research the different types and the pros and cons of each.

I did the research for you.

Here are some of the best carbon media for media reactors.


What is activated carbon and what are the different types?



Activated carbon is a very effective type of chemical filtration that can be used on your saltwater tank to improve water quality and clarity, remove odors and contaminants, dissolved organics, and much more.

The two most important factors with respect to activated carbon are:

  • The size of the particles
  • The shape of the particles

Smaller particles that are round will pack better and provide more surface area.

This gives you more filtration capacity and increases the carbon’s effectiveness.

Large particles that are irregularly shaped provide less surface area and also will pack less. Just the opposite of smaller particles, they provide less overall surface area and will be less effective.

Activated carbon is considered to be the most popular and affordable options to use in an aquarium media reactor.

There are 3 types of activated carbon used on marine tanks.

Bituminous carbon

AquaMaxx Bituminous Carbon

This is the most popular carbon that is used in marine tanks. It is affordable and doesn’t create much dust which is important to not allow inside the tank.

This carbon is easy to use and maintain which is a good choice for beginners or anyone looking for a low-cost option.

The downside of this carbon is it has a lower pore size which makes it not as effective as some others. There are special grades of Bituminous carbon available which has a larger pore size and it will be more effective.

Lignite carbon


Lignite carbon is used by people who want a high-performance carbon and don’t mind the extra effort required to maintain it.

This carbon has an average pore size which makes it a great choice for the removal of organic compounds. Also, any contaminants in the water will be easily removed.

The biggest concern with Lignite carbon is it’s a dusty carbon and it takes more effort to rinse the dust particles out.

It’s best to use this carbon in a reactor where it’s easier to rinse clean. If you use it inside a filter bag, it is harder to rinse clean. It can take several minutes to rinse in a filter bag compared to seconds with a reactor.

Rox 0.8 carbon

ROX 0.8 Carbon

Rox 0.8 carbon will give you the best-combined benefits of both Lignite and Bituminous. It comes in a fine pellet size which maximizes the surface area of the carbon making it very effective.

This carbon is the hardest of the 3 types and is very easy to keep clean. It is not a dusty carbon and won’t add anything bad to your water.

Rox 0.8 carbon is the most expensive carbon but you don’t need to use as much of it as the others. So there is a trade-off there. It may cost more but it lasts longer and is actually the best bang for your buck.


Best activated carbon for media reactors


  • AquaMaxx Rox 0.8
  • Red Sea Reef Spec
  • Kent Marine Reef


AquaMaxx Rox 0.8

AquaMaxx Rox 0.8 is the highest grade acid washed extruded carbon available. It reduces and eliminates organic pollutants, odors, and discoloration from aquarium water.

Features and specs:

  • Fast-acting carbon
  • Steam activated and acid-washed
  • Low dust content
  • Easy to rinse
  • Small pellet size for maximized surface area
  • Iodine number: 1000 min
  • Hardness: 97 min
  • Particle size: <0.6 mm
  • PH: Neutral

Although this carbon will cost more to purchase, it will last longer as you don’t need to use as much as others.

Directions: Rinse before use. Use 1/4 – 1/2 cup for every 50 gallons of aquarium water volume. Maximum efficiency will be when used inside a media reactor.

Red Sea Reef Spec

Red Sea Reef Spec Carbon has unique technical characteristics that make it a very popular choice. This carbon has a micro/macro porous structure which gives it a high absorption capacity and extraction of organic pollutants.

Features and specs:

  • Ultra low phosphate output
  • Ultra-low ash content
  • Rapid removal of organics
  • Small porous structure
  • Iodine Number: 1000
  • Shape: 0.6 – 2.3 mm flakes
  • PH: >8

This carbon is more affordable than the Rox 0.8 carbon and is an excellent choice.

Directions: Rinse before use. Soak in RO water until all air has been released from the pores. Use 100 ml for every 50 gallons of aquarium water volume. Place in an area of active flow between 250 – 400 GPH.  Replace every 1.5 – 2 months.

Kent Marine Reef

If you are looking for a more affordable activated carbon, check out Kent Marine Reef Carbon. This is a pellet form of Bituminous coal-based carbon. It is effective in removing odors, organic pollutants, and toxic gasses in aquarium water. Kent Marine is a soft carbon and can release dust into your system if stirred too rapidly.

Features and specs:

  • Best suited for removal of large organic molecules
  • Does not clog easily
  • Does not leach phosphates
  • Pore size: 20 – 2000 Angstrom range
  • Ash: < 0.2%

Directions: Rinse before use. This carbon is dusty and will require some effort to rinse properly. Reef carbon is very active so you can use a lesser amount without losing effectiveness. Use 1 cup for every 100 gallons of aquarium water volume. Best results are found when only used for a few days per month. Continuous use is not required. Do not use this carbon in areas of strong water flow where it could be stirred rapidly to prevent dust and the particles from breaking apart.

How much activated carbon should you use?

The amount of activated carbon to use will vary based on the type, manufacturer, tank size. Always follow the directions for the type of carbon being used.

On average it is common to use around 1/2 cup per 50 gallons of total water volume.

It’s always best to start with a small amount and work up to the full amount needed.

Here is a general guide to follow for activated carbon use:

Rox 0.8 – 1 tablespoon for every 10 gallons total water volume

Lignite – 1.5 tablespoons for every 10 gallons total water volume

Bituminous – 2 tablespoons for every 10 gallons total water volume

Proper water flow rate through the carbon media reactor

When using activated carbon, you will be able to use it either inside of a filter bag and placed into an area of active flow or use a media reactor.

Using a media reactor is the most effective way to use activated carbon and you will see better results overall.

Ideally, when used in a reactor, the carbon should not tumble. This will cause a breakdown of the media, lose its effectiveness, and release dust into your system.

Low flow is important and you should aim for around 250 – 400 GPH of water flow through the reactor.

It’s better to use a media reactor that has an adjustable flow valve so you can dial in the proper flow rate.

Best carbon media reactor

There are several types of media reactors available to choose from. Media reactors are quite affordable and are a very effective piece of equipment to have. Although they are not necessary, they sure are nice to have.

If you are on a budget, I recommend the AquaMaxx media reactor and the TLF 150 Phosban reactor. Both are very effective when using activated carbon and they are easy to set up and maintain.

Both are available at Marine Depot here.

Another great option is the AquaMaxx XXL dual media reactor for GFO and carbon. If you have a larger aquarium and want to run GFO and carbon together, this is a perfect choice.

Available at Marine Depot here.


Reef chemistry calculator

Here is a quick calculator to show how much carbon you need to use for your tank.

Marine Depot calculator