Maintaining an aquarium (saltwater or freshwater) is a tedious task. It requires constant attention and effort from the keeper. And sometimes, despite all your effort, all can quickly go south!

At times, even the premium aquarium filters have a hard time maintaining the environment of your tank. Chances are, you tried several alternatives. However, the solution of cleaning or replacing the filtration media can do more damage to it than help.

They can eliminate valuable bacterial settlement, and you have no reset option after such a mistake. Therefore, one way to cope with this is to use the best aquarium media reactors, which is a tube-like structure known to perform effective filtration.

Before jumping into the details let’s take a look at our top choices –

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What Is an Aquarium Reactor?

An aquarium media reactor is one of the alternative pieces of aquarium equipment that boosts improvement and automation to the process of bringing fresh, clean water to the inhabitants of the aquarium.

You can think of it as a component of the filtration mechanism through which you keep the tank water in excellent shape. The aquarium reactor is made up of a pump, plastic chamber, tubing, and some valves.

Furthermore, the chamber is a place where the media is implanted. Media is an element that operates with water to enhance its quality.

Whereas, the tube flows water from your tank or sump through the pump and in the plastic chamber.  Finally, it goes out again to the tank or sump.

best aquarium media reactor

Why You Should Consider Buying an Aquarium Reactor


Most of the time, if your regular filter is doing its job correctly, then you may not need an aquarium reactor. It mostly depends on the contents and size of your tank.

Often, it is better to start with a standard filter and later add a media reactor if you realize that you need one. That said, if you happen to have a big reef tank, then an aquarium reactor is worth the investment.

You can buy an aquarium reactor for a lot of reasons such as, if you’ve silicates and phosphates in the source water, if you want to keep Small Polyp Stony (SPS) corals, and if you’re facing minor or major problems regarding the algae in your tank.

In addition to that, you can also purchase it to enhance the water quality of your reef tank and take it to the next level, if you want to regulate your reef tank dosing or water purification, and if you’ve detected substantial nitrates and silicates in the water.

Different Types of Aquarium Reactors and Their Purpose

The reason most people want to keep a saltwater aquarium is that they adore the fish and corals in the tank, and they also love the challenges that come with creating a healthy and natural environment for marine life.

Moreover, much of the hard work goes into maintaining the water parameters of the tank. Here aquarium reactors can help you keep it in the normal range.

Remove Phosphate

Phosphates in the aquarium water decrease the amount of magnesium and calcium that can be dispersed in the water. They are vital nutrients that act as fertilizers, and their decline can cause an increase in algae growth.

Some people rely entirely on the aquarium reactors to eradicate phosphates from the water.

Remove Silicates

Silicate is a chemical that is also in your aquarium water. This, too, acts as a fuel of producing more algae, especially diatoms, which can be a problem.

They are introduced in the water when you are feeding the fish, and they can also arrive and foster through the tap water.

Remove Nitrates

Nitrate is an ion that is a natural offshoot of the biological filter of your tank. So identifying nitrates in the aquarium is a good thing because it means the screen is running well.

Furthermore, nitrates are known to be less lethal to your aquarium than ammonia. However, nitrates will amalgamate and cause complications in the tank. It is also known to act as an algae fertilizer and can cause problems to some invertebrates.

Increase Calcium Levels

One of the essential metals in your tank water is calcium. It is crucial for the shell or skeletal growth for nearly all of the marine creatures in your aquarium. A calcium reactor can raise the chemical levels in your tank.

The calcium reactor works in two different ways; calcium carbonate can be used as the media/substrate. Carbon dioxide is added into the reaction chamber to decrease the pH level of the chamber, and this dissipates the calcium carbonate.

This, in turn, increases the volume of decomposed calcium present in the water, which then goes back to the tank. Another way is the kalkwasser reactor. You can add it to the chamber and splash it in the tank at a low dosage to increase the calcium levels.

Aquarium Reactor Media (And What They Are Used For)

Granular Ferric Oxide (GFO)

Granular Ferric Oxide, known as GFO, is a famous aquarium reactor media because it’s highly effective at removing phosphates efficiently out of the water. It will not only remove phosphates but metal ions as well.

This can be a bit of a disadvantage because you might need some of the metal ions to remain in your tank water. Therefore, if you want to choose Granular Ferric Oxide as a media reactor, then you need to have a test kit to observe the water parameters of the tank.


Biopellets are made from bacteria, and they are used to boost the biological filter significantly. What the micro bio pellets do in a reactor is that they create an ideal environment so that the beneficial bacteria can grow and thrive.

Increasing the population with this method helps the bacteria to maintain the water parameters within range. You have to continue feeding the bacteria the bio pellets so that the colony keeps growing.

After you have achieved the level that you want, you need to switch things back to a normal mode before it gets out of control — the bio pellets decrease nitrates by enhancing the production of bacteria that devour the nitrates.

Activated Carbon

Activated carbon has been a regular media reactor for the aquarium keepers. It is an economical, porous substance which ties and efficiently removes some of the unwanted materials in the tank.

To boost the effectiveness of the activated carbon, you can use it with a reactor, which will ultimately improve the water flow of your tank.

Calcium Carbonate

Calcium carbonate, also known as crushed coral, can dissolve in the water and boost the calcium concentration in the tank. Its natural porous texture promotes the carbon dioxide infiltration, which ensures a consistent dissolution rate.

Factors to Consider Before Selecting the Best Media Reactor Brand


There are a lot of sizes to choose from, so you should select the one that is compatible with the size of your tank. Since most manufacturers design different sizes for different types of tanks, you will have an easier time selecting it


This is one of the essential components of an aquarium reactor. So you have to choose a brand that produces a reliable and stable pump. You can also buy a reactor that does not include a pump, and you can buy the pump separately.

The pump is like a vital organ because it does all the hard labor of transferring the water right in the reaction chamber. So before buying the pump separately or with the reactor, you should thoroughly read the reviews on it.

This way, you will also know the significance of the pump, and it will give you an idea on which brand to choose for a stable pump.

Design and Quality

As we have mentioned earlier, reactors are a chamber, a pump, and some valves that will help you accommodate the water flow inside the chamber or get in the chamber to load it or change the media.

So, one of the most vital features while choosing a proper aquarium reactor is to see if it features high-quality materials and whether it is built of sturdy craftsmanship.


When it comes to choosing the best aquarium reactor, other than features, you also have to consider its cost. However, one vital factor to check upon is to see if your desired model includes a pump.

This is because buying an expensive aquarium reactor which has no pump will cost you more in the future because you have to buy it separately. But this also doesn’t mean you have to select an overpriced model which includes a pump.

Best Aquarium Media Reactor Reviews

To save you from the trouble of going through a cornucopia of products, we have selected a few with detailed breakdowns.

Here are our top 6 best aquarium media reactors and reviews.

1. Two Little Fishies Filter Media Reactor

The Two Little Fishies Filter Media Reactor is an efficient device that one can use to improve the water filtration system of your reef tank. It is an acrylic reactor measuring 14 inches in height and 3.5 inches in diameter.

The product comes with a lot of features and is quite affordable. You can install it in small or big aquariums up to 150 gallons. You can also purchase more than one unit for large tank sizes.

The equipment doesn’t include a pump or a hose. It has a water flow rate, which ranges from twenty to thirty gallons per hour, and anything above this rate may grind the Phosban. However, a pump with a higher flow rate (GPH) will also work well.

Moreover, the device has a knob that enables smooth flow control. It also has output and input hose connection, which bends at a 90-degree angle. You can also rotate the pieces for fitting it securely during installation.

The equipment has an up-flow feature, which is known to provide adequate filtration. It pushes the water from the bottom to upwards, and this provides an even circulation of water via the media.

Moreover, it restrains water channeling. The reactor can handle up to 200 grams of Phosban; if you use some other media, it can hold up to 5 inches. It is compatible with bio pellets and purigen.


  • Compatible with bio pellet and purigen
  • Budget-friendly product
  • Has a steady flow control


  • Doesn’t include pump or hose
  • The screw-top is difficult to open

2. AQUATOP MR-20 Reactor

AQUATOP MR-2O is the best aquarium reactor in the market. The brand is known to produce reliable and efficient reactors with multiple features. They also have different kinds of media filters to use with the reactors.

This device is all in one reactor because it includes a sediment release filter, a submersible pump, and all other components that you require for plumbing, so you don’t have to buy things separately.

The reactor is acrylic and measures up to 15 inches tall and 2.5 inches in diameter. It is suitable for reef tanks ranging from fifty to seventy-five gallons. Furthermore, the equipment is quite easy to set up since it works with tank fittings or sump.

You get two connector pieces with this reactor. It also contains a suction cup holder in the bottom and a hook at the top to hold the device securely. Despite all these features and components, the product remains quite budget-friendly.

This reactor uses the up-flow mechanism, which is good because the filtration process will be efficient. Furthermore, the device features an easy to remove the top.

This is made possible through a recessed O-ring. Another element that makes this product worthwhile is that its SWP-230 flexible water flow-pump, which maintains a silent process of filtration. It is known to work with various filter media.


  • Includes sponges, pump and hoses
  • It’s an all in one aquarium reactor
  • The pump maintains silent filtration


  • The pump doesn’t provide enough capacity for bio pellets
  • Tubes are a bit delicate

3. AquaMaxx Fr-se Filter Media Reactor

The AquaMaxx Fr-se Filter Media Reactor is a hang-in device so it can be attached to the sump or fish tank. You can use the filter for more than one purpose, but how much it filters is determined by the media.

The reactor is suitable for smaller tanks, and its canister features cast acrylic build. Its strong structure ensures efficiency and durability. The device features an effective up-flow mechanism.

This mechanism will effectively suspend and uniformly spread the filter media to increase 100% contact with the reef tank’s water. How the up-flow feature works, is that the water goes down through the filter via the center internal tube.

When it reaches the bottom, it gets propelled upwards and directly comes in proximity to the media, such as GFO, after which the water finally returns inside the tank.

Furthermore, to keep the outlet and inlet intact, a structure has been constructed which can keep both the components safe. Since it is a multi-purpose reactor, it can not only remove phosphate with its granular ferrous oxide (GFO) but also use activated carbon.

You can use GFO on 150 gallons tank, activated carbon on 75 gallons, and with bio pellets, you can use up to 50 gallons. This ratio will give you optimal performance.


  • Suitable for smaller reef and marine tanks
  • Versatile device lets you use different filer media
  • Includes bracket to keep outlet and inlet tubes intact


  • The water tube and pump are sold separately
  • Vague instruction manual

4. Accel Aquatics Filter Media Reactor FR-30

If you’re looking for a reactor that has been designed explicitly for bio pellets, then the Accel Aquatics Filter Media Reactor FR-30 is for you. Although you can use this device to fluidize GFO to remove the phosphate from your tank.

The reactor is designed in such a way that it can fluidize the bio pellet media even without using high flow. This is done by a unique flow stimulator known as the eductor placed in the reactor, which boosts turbulence.

The robust water movement propels the bio pellets continuously. It also has an inverted cone-shaped bottom, which prevents the media from settling or clumping together at the bottom.

Furthermore, the equipment is pretty easy to install and manage. You can adjust the flexible inlet to your preferred setting of the fish tank. It is also effortless to add the media.

All you have to do is open a tiny screw plug situated at the top, unlike other reactors you don’t have to remove the lid altogether. As mentioned earlier, you can use other filter media on this reactor.

This includes carbon and granular ferrous oxide (GFO). You can use the water pump that can manage the flow specifications of the filter media that you have chosen.


  • It has been specially built for bio pellets but also allows other filter media
  • Features strong eductor to increase turbulence
  • Contains an inverted cone-shaped bottom


  • Doesn’t include tube and pump
  • Not very suitable for carbon

5. Innovative Marine Minimax Media Reactor

The Innovative Marine Minimax Media Reactor is indeed a piece of creative and handy equipment, which ensures that your reef tank maintains an environment that is devoid of excessive nutrients.

It is an all in one media reactor which is compatible with GFO, carbo, and bio pellets filter media. The device has a unique structure and easy to accommodate.

You don’t need any external components like PVC pipes, ball valves, adjustable pipes, thumb screws, etc. to use this reactor because it can operate efficiently on its own.

This is the best device to have when you need a GFO or carbon reactor for a small reef aquarium or any other nano tank. It also works very silently, so you will have no disturbance issues.

Unlike other reactors, this one contains internal chambers that are quite easy to remove and clean. It is built of acrylic so it will be able to last for a long time. The top and bottom parts of the reactor featuring black acrylic paint gives it a stylish look.

With the suction cups, you can quickly secure the reactor to the side of the aquarium. One can find the pump underneath the reactor. Furthermore, the double chambers will allow you to use the device for organic absorption and carbon media.


  • Takes very little time to change filter media
  • Very affordable
  • Removable chambers are easy to clean


  • Flow rate can be difficult to adjust
  • The press sometimes falls between the outer and inner tube

6. AquaMaxx Filter Media Reactor

The AquaMaxx Filter Media Reactor is an efficient piece of equipment that has been specifically designed for reef and marine tank use. It measures up to 15.3 inches in height and 3.9 inches in diameter.

The reactor is a versatile device, so you can use any type of filter media that you want to clear your reef aquarium from discoloration, odors, and pollutants. It can successfully fluidize granular ferrous oxide and carbon to remove phosphate from the tank.

Like most reactors, it uses an up-flow mechanism. This design keeps the media stationary in the reactor and then uniformly spreads out to be propelled upwards to come in direct proximity to the filer media. It also prevents water channeling.

The reactor can be set up in two different ways, and you can either place it right in the tank or use an external adapter to hang it outside the reef aquarium. So, you can choose any one of the methods that you like.

You don’t need to worry about the reliability of the reactor because it has been extensively examined in saltwater habitat. The build quality is of a simple acrylic structure, which is robust and sturdy.

This computer designed construction with high-quality materials will last you for a long time.


  • Suitable for reef and marine tanks
  • Compatible with various types of filter media
  • Very budget-friendly
  • Made of sturdy and durable materials


  • The tube and pump are sold separately
  • Unclear instruction manual

Wrapping Up

Sometimes having a standard aquarium filter isn’t enough to maintain the environment of your tank. For this reason, you should consider buying the best aquarium reactor to keep your tank healthy and vibrant.

It is up to you to choose the best aquarium reactor out of the ones reviewed above. Still, we recommend the Accel Aquatics Filter Media Reactor FR-30 for its unique water flow system, affordable price, and excellent features.

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