Top 7 Best Biopellet Reactors [Reviewed & Explained]

Most beginner aquarium enthusiasts make a similar mistake. They don’t allow nitrifying beneficial microorganisms to grow. These organisms, especially bacteria, break down ammonia into nitrite, and ultimately into nitrate. 

Given enough time and appropriate nutrition (carbon), these bacterial colonies sustain themselves in the gravels and filter sponges. However, we use biopellets like GFO, carbon, polymers, and sawdust to further support their existence.

Thanks to the porous properties and carbon structure of biopellets, the bacterial colonies are given enough space to grow and do their job of breaking down the organic pollutants more efficiently.

Among the biopellet reactors we tried, the Reef Octopus BR70 Biopellet Reactor is overall the most convenient and efficient product. The bottom cone and mesh design, aided by durable material and a smaller footprint, makes it the best choice for the reactor. 

Hi, I’m Ushnish, an aquarium enthusiast with a decade of experience, will be reviewing a few Biopellet reactors today.

Best Biopellet Reactors in 2024

1. Lifegard Aquatics Turbo Reactor - Medium Side Flow

Lifegard Aquatics Turbo Reactor

Suitable for small to medium size tanks, Lifegard Aquatics Side Flow Reactor can be used with biopellets like GFO and carbon beads. Throughout our testing, the pump and the reactor performed pretty consistently. 

However, because the reactor isn’t manufactured for bigger aquariums, the pump flow may not be adequate to rotate water in larger tanks. 

Important Features

  • Corrosion Resistant 

Being built with polymers and rubber sealers, there is no possibility of corrosion in this biopellet reactor. Despite the constant presence of air, the water quality isn’t affected due to corrosion. However, the rubber sealants may erode over time. 

  • Side Flow Turbo

Lifegard Aquatics uses the side flow turbo design to ensure a turbulent movement of water and biopellets. As the pellets “vortex” in the water, the reactor achieves maximum efficiency and minimum pellet erosion

  • Aquarium Flow Control

The higher the flow of water, the faster you’ll erode the biopellets. With aquarium flow control on the Lifegard Aquatics biopellet reactor, you can optimize input flow to fit your requirements better. Moreover, a slower rotation in this case is much more effective than a faster operation. 

  • Minimum Space Requirement

This biopellet reactor is relatively small in size and can be fitted without pipes and valves. The small 5 x 5 x 16 inches dimension of the product has a negligible footprint and can be squeezed between your filters.  


  • Made from durable and high-quality acrylic.
  • Easy to set up. Shouldn’t take you more than 10 minutes to set it up. 
  • Zero requirements for pipes and valves.
  • Large O-ring seals to ensure zero water leakage. 


  • Underwhelming pump performance. But, as the water flows from the sides, the speed should be adequate for most aquariums. 
  • The product is a bit noisy. 
  • Pricing is on the higher side considering the features offered. 

Lifegard Aquatics Medium Side Flow Turbo Reactor is the right one for small to medium-sized tanks. 

You can check out The Aquarium Guide’s article on the Best Pond Pump.

2. Reef Octopus BR70 Biopellet Reactor

Reef Octopus BR70 Biopellet Reactor

For those who’re looking for a durable, efficient, and cost-effective biopellet reactor, the Reef Octopus BR70 is for them. Built with premium-grade acrylic, this reactor can be used for tanks up to 80 gallons. 

Although it lacks in the accessories department with the absence of pump and fittings, it regains the reputation with performance. 

Important Features

  • Fluidizing Cone Bottom Design

In a proprietary design, the Fluidizing Cone Bottom of BR70 enables the biopellets to always stay suspended in the water and evenly disperses the flow upwards. 

This allows longer contact between water and pellets without restricting the flow.

  • Mesh Screen Protection

At the top, mesh screen protection allows the biopellets to move freely through the unit without clogging the output or disrupting the water flow. 

  • Smaller Footprint

BR70 has one of the smallest footprints among biopellet reactors in the market. With only 3.875” X 3.875” in dimension, it can be squeezed anywhere between your protein skimmers to the back of the tank. 

  • 400mL Biopellet Load Capacity

The reactor unit holds 400mL of biopellets. However, as the unit doesn’t come with a bundled pump, we recommend Sicce Syncra Silent 1.5 Pump (357 GPH) to move and suspend the pellets efficiently.   


  • Specifically designed for solid carbon dosing biopellets.
  • Reactor leads are fastened with screws to prevent leakage.
  • Biopellets don’t clog the reactor.
  • Doesn’t require a heavy flow rate.


  • Need Valves for flow control
  • The pump isn’t included in the package

The Reef Octopus BR70 is perfect for power users with larger aquariums in confined spaces. 

3. Accel Aquatics BioPellet and Filter Media Reactor - FR-16

Accel Aquatics BioPellet and Filter Media Reactor - FR-16

The FR-16 is the smallest model in the Accel Aquatics BioPellet range. With a media capacity of up to 300mL, this biopellet reactor is suitable for small to medium aquariums. 

As a few technologies have been used to create a powerful water flow, the product may seem a bit loud for living room usage.  

Important Features

  • Use of Penductor

A penductor or a flow accelerator has been used in the model to keep the biopellets moving in a strong turbulent motion. The flow accelerator pushes the water flow through a narrow nozzle to force the pellets to move faster.

  • Inverted Conical Bottom

The FR-16 is designed to generate a turbulent and faster flow without needing a powerful pump. The inverted conical bottom, below the vinyl tube, works as an extension of the accelerator and doesn’t let the pellets clump or accumulate in the bottom. 

  • Need for a smaller pump

Thanks to the flow accelerator and inverted conical bottom, you don’t need to use a powerful pump. A smaller 150-300 GPH pump is adequate for the most effective pellet movements.

  • Suitable for nitrate-reducing biopellet

Although the reactor was designed for nitrogen-reducing biopellets like the NP-Active Pearls, it works quite well with GFO and carbon pellets. 


  • Small Footprint of only 5.5” in diameter
  • More powerful water flow at a much lower pump force, even up to 25%. 
  • The pricing of the product is in the affordable and cost-effective range. 


  • The FR-16 biopellet reactor is loud. With pellets tumbling and water accelerating, it’s a bit louder than the competition. 
  • The pump and tubings aren’t included. 

The FR-16 biopellet reactor is optimum for smaller and medium aquariums with high-bioload fish like Oscars, Arowana, and Cichlids.  

4. Two Little Fishies ATLPBR150 GFO PhosBan Reactor 150

Two Little Fishies ATLPBR150 GFO PhosBan Reactor 150

With the capability to cater to aquariums up to 150 gallons in size, PhosBan 150 biopellet reactor is suitable to house 200 grams of GFO and carbon pellets. Despite its lack of easy installation, the cost-effectiveness trumps it all.  

Important Features

  • Use of Upflow Technology

A dispersion plate is used to achieve media fluidity in the reactor chamber. The Upflow Technology, aided by the narrow design, helps keep the biopellet media suspended and moving. For carbon, it’s recommended to fill the entire column for maximum effectiveness.

  • Need for a smaller pump

A smaller pump of a maximum of 20-30 GPH is recommended for ATLPBR150 to function. Anything more than that will move the pellets faster and put undue pressure on the column walls.

  • Corrosion resistance

Premium-grade vinyl and rubber O-rings are used to manufacture the model. While leakage is prevalent in a few joints, most of the unit seems quite durable.

  • Value for money

The price point of this product is its primary selling point. Despite the presence of other premium products, the cost-efficiency of this model entices a lot of beginner aquarium enthusiasts. 


  • Making it one of the most popular biopellet reactors out there, PhosBan Reactor 150 is cost-effective and durable,
  • The recommended flow rate of only 20-30 GPH makes it less noisy and more efficient. 
  • Easily removes Green Hair Algae from larger tanks.


  • Difficult to maintain and disassemble. The hanging bracket is attached to the base. 
  • Poor direction for installation. 
  • Material quality issues and leakage. 
  • The pump and accessories aren’t included in the product. 

PhosBan Reactor 150 is suitable for hobbyists on a constrained budget and tanks with high algae infestation.

5. Aquatop MR-30 Media Reactor

Aquatop MR-30 Media Reactor

The Aquatop MR-30, with 152 GPH capacity and support of up to 200 gallons, is one of the most cost-effective biopellet reactors out there. Although cheaper, the reactor comes equipped with a pump, accessories, and a reliable filtration system. 

Important Features

  • Reverse water flow design

The efficiency of MR-30 is maximized through a reverse flow design channeling the water through both the biopellet media and sediment discharge filter. 

  • High-quality acrylic

The product uses premium-quality acrylic for durability and zero flaking. Therefore, harmful polymers aren’t released into the water—keeping the fish safe.

  • Recessed O-ring

MR-30 uses seal-tight recessed O-rings to ensure zero leakage and easier removal of the lid. The O-rings are easily replaceable and don’t corrode in the long term.  

  • Adjustable water flow

The SWP-360 pump included with the product is empowered by the bundled accessories and adjustable water flow feature. Adjust the water flow to keep the biopellets suspended and slowly moving. 


  • Easy to put together. 
  • Mechanical sponges are included.
  • Cost-effective
  • Every accessory and pump are included. 


  • Larger footprint compared to efficiency. 
  • The pump is a bit underpowered for GFO suspension. 
  • Carbon Dose clogs the biopellet reactor.

MR-30 is perfect for larger aquariums with small spaces to house a biopellet reactor. 

6. Two Little Fishies ATLPBR550 GFO PhosBan Reactor 550

Two Little Fishies ATLPBR550 GFO PhosBan Reactor 550

Similar to PhosBan 150 but with adequate column space and flow to support aquariums of up to 550 gallons, the PhosBan Reactor 500 is a fan favorite. In comparison to the former one, Phosban 550 has a max media capacity of 750 grams and a max flow rate of 250 GPH.

Important Features

  • Upflow Technology

This 550 variant of PhosBan uses the same Upflow technology as its smaller version. The flow of water is directed from the bottom by reflecting it on the dispersion plate and through the biopellet media.  

  • Small footprint of 4.5” X 6.5”

The 550 reactor has a smaller footprint per gallon than the 150 version. With only 4.5” in length and 6.5” in width, it’s easier to place it near the aquarium.

  • Higher capacity for larger aquariums

Mitigating the issue of using multiple biopellet reactors, PhosBan Reactor 550 nitrifies larger tanks with ease. You also can use it for your smaller aquarium for faster disintegration. 

  • Perfect for HOB applications

The accessories and built-in hanging bracket of the PhosBan 550 make it perfect for hang-on-the-back (HOB) operations. It also includes a ball valve for flow control. 


  • Includes necessary accessories and a ball valve. 
  • Easy to install and remove
  • Cost-effective


  • O-rings are brittle and may lose shape.
  • The build quality could’ve been a little better.
  • A pump isn’t included in the package.

PhosBan 550 is adequate for larger 500+ gallon aquariums.  

7. OCTO OCT-MF300B 2.5 Inch Media Reactor

OCTO OCT-MF300B 2.5 Inch Media Reactor

Equipped with every necessary accessory and a reasonable pump, the OCT-MF300B biopellet reactor is a beast. Empowered by its 2.5” column and 95 GPH max flow, this product is capable of nitrifying your medium-sized aquarium within a week. 

Important Features

  • Cone Bottom Design

As with other Reef Octopus products, OCT-MF300B also equips itself with a cone bottom design for better water flow and media suspension. The design ensures that the media, especially GFO and carbon, don’t accumulate near the bottom. 

  • HOR capability

Your MF300B can be hung over rims (HOR) for better support and efficiency. However, due to its smaller footprint, it can be squeezed almost anywhere.

  • OTP300 Feed Pump

OTP300 feed pump, although not quite powerful, is adequate for media suspension and flow necessary for bacterial operations.

  • Customizable to your needs

Thanks to the product’s versatility and bundled equipment, it can be used as a filter, reactor, skimmer, or even SUMP.  


  • Easy to set up
  • Large media capacity for medium aquariums
  • Comes equipped with a pump and all accessories
  • Great as carbon and GFO reactor


  • Absence of foam filter. Sludge can build up over time. 
  • The pump is too powerful for GFO and the flow control system doesn’t work well

OCTO OCT-MF300B is best for medium tanks with high amounts of ammonia and hair algae. 

Buying Guide

We’ve tested and reviewed only a few of the best biopellet reactors. However, as the list isn’t exhaustive, there are hundred other reactors available in the market to fulfil your purpose. In this section, we’ll discuss the parameters that we’ve considered while reviewing the products. 

Treatment Capacity

When buying a biopellet reactor, always consider treatment capacity as the primary contributing factor. Disregarding wastage, you may choose a larger capacity model for a smaller aquarium. But, a smaller capacity reactor can’t cater to a larger volume.  

Note: 1 US gallon (liquid) is equal to approximately 231 cubic inches or 3.78 liters.

Reactor Design and Configuration

A lot of different design elements are often embodied by manufacturers to maximize operational efficiency. However, not every fancy name is effective in nitrifying your aquarium. 

Ensure slow movement of pellets, full circulation of flow, suspension of beads, and dispersion of water while choosing your next biopellet reactor.   

Process Control

A biopellet reactor, at most, is capable of offering monitoring and flow control in terms of process control. Make sure that your preferred product comes with both of these features. 

However, the flow control component is more dependent on the pump than the reactor itself. 

Maintenance Requirements

You would often need to clean your reactor and replace the beads to sustain its performance. Easy installation, removal, cleaning, and pellet replacement should be considered when buying a biopellet reactor. 

A more durable reactor should allow you to clean the products a few times before giving up on the body or the O-rings. Clogging of the pipes and pump breakdown are also prevalent In some cheaper alternatives. 

Pump Power Consumption

As you need to keep your reactor running 24×7, power consumption should be given due weightage. If you have multiple aquariums and reactors, it may add up to a significant number. 

Note: flow control systems often put a strain on the pumps and increase motor resistance. It can increase the power consumption of the setup. 


You shouldn’t neglect the track records of the manufacturer, model, and user experiences when buying the biopellet reactor. You can expect to get better customer support, product support, and replacement parts from a reputed manufacturer than a terrible one. 


While not in the exorbitant zone, biopellet reactors don’t come cheap. Ranging from a few dollars to a few hundred, determine what’s best according to your budget. Always remember that the fundamentals of all the reactors are mostly the same. 

Leakage, durability, power consumption, maintenance, and support mostly contribute to the difference in pricing. 


How long do biopellets last? 

While it depends on the composition and porosity of the pellets, carbon pellets should last you about 6 months, and GFO pellets should last about 4-8 weeks. Your first batch of pellets may dissolve quickly, but it would stabilize after a few rotations. 

How long does it take for biopellets to start working?

 A few weeks, optimally 2-3 weeks, are required for biopellets to start working. Keep patience and let the bacterial colony grow over time.  

What is the flow rate of a biopellet reactor?

Biopellet reactors are best kept at an internal flow rate of 90-150 GPH. The rule of thumb is to allow the biopellets to move within the column in a regular laminar flow.   

The Bottom Line

After careful consideration and extended usage, we believe that the Reef Octopus BR70 is the best option as your biopellet reactor. While a bit on the costly side, it has mesh screen protection and a bottom cone design that is unparalleled in terms of convenience and efficiency. 

However, you may need to buy a separate pump from the same manufacturer to maximize its performance.

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