Best Reactors for Reef Tanks: Five Media Filtration Options
The best reactor for a reef tank depends on tank size, available space, and the media you plan to use. The Two Little Fishies PhosBan Reactor 150 is best for systems up to 150 gallons, while its Nano model is suited to smaller aquariums and frag tanks. The AquaReady FR-SE offers a hang-on-back format, and the AQUATOP MR-30 includes a pump. The Bulk Reef Supply model lists a 357 GPH flow rate and a compact, low-profile design.
| Reactor | Best suited for | Listed standout |
|---|---|---|
| Two Little Fishies PhosBan Reactor 150 | Tanks up to 150 gallons | Up-flow design; multiple media types |
| Two Little Fishies Little Reactor Nano | Nano tanks and frag tanks | Compact design for tanks up to 75 gallons |
| Bulk Reef Supply Media Reactor | Buyers comparing flow-rate specifications | 357 GPH; up-flow filtration |
| AQUATOP MR-30 | Buyers wanting a reactor with a pump | Includes pump, tubing, and mount |
| AquaReady FR-SE | Hang-on-back installations | Adjustable fittings and media capacity details |
Two Little Fishies PhosBan Reactor 150
Best for: Reef keepers with aquariums up to 150 gallons who want a reactor designed for chemical filter media. Its bottom-fed up-flow design pushes water through a dispersion plate, which helps distribute water through the media.
The listed media options include PhosBan and other chemical media, as well as activated carbon. For larger systems, the manufacturer information says multiple reactors can be used. This makes it a useful option for buyers who want to select media based on their filtration needs.
Limitation: The listed tank-size recommendation is up to 150 gallons per reactor. Larger aquariums may require more than one unit, and the supplied details do not identify an included pump.
Two Little Fishies Little Reactor Nano
Best for: Owners of nano aquariums, smaller reef tanks, or frag tanks where equipment space is limited. The compact model is specified for aquariums up to 75 gallons and uses an up-flow design with a dispersion plate.
Choose this reactor if a smaller footprint matters more than the larger capacity of the PhosBan Reactor 150. Its listed design provides similar up-flow features in a unit described as about half the size of the larger model.
Limitation: The stated recommendation is up to 75 gallons, so it is not the listed choice for larger aquariums. The supplied product details do not specify an included pump.
Bulk Reef Supply Media Reactor
Best for: Buyers who want a reactor listing a specific flow rate and an up-flow filtration design. The product name specifies 357 GPH and describes the unit as suitable for fresh- and saltwater aquariums, with a compact, quiet design and low-profile mounting.
Its listed features may suit shoppers comparing flow-rate information or looking for an easy-mounting format. Use the stated 357 GPH as a specification to compare with the flow requirements of your chosen filter media and setup.
Limitation: The provided product information does not list tank-size guidance, included components, or media capacity. Confirm those details before choosing it for a particular reef system.
AQUATOP MR-30 Media Reactor
Best for: Reef keepers who want a reactor package that lists a pump, tubing, and mount. The MR-30 is described as a 152 GPH up-flow system for saltwater or freshwater aquariums, with sump or hang-on setup options.
It is listed as compatible with carbon, phosphate sponges, and resin-based media. The package includes an SWP-360 submersible pump with a sediment discharge filter. Its acrylic chamber has a recessed O-ring lid for access when replacing or cleaning media.
Limitation: The listed flow rate is 152 GPH. Check that this suits the media and aquarium setup you intend to use; the provided details do not give a recommended tank volume.
AquaReady FR-SE Hang-On-Back Reactor
Best for: Aquarists looking for a low-profile hang-on-back reactor with adjustable inlet and outlet fittings. Its up-flow design sends water from the bottom upward through the media. The listed capacity is approximately four cups.
The product is intended for carbon, GFO, or biopellets, with different recommended tank sizes by media: up to 150 gallons for GFO, 75 gallons for carbon, and 50 gallons for biopellets. This media-specific guidance helps buyers compare capacity against their intended use.
Limitation: The recommendations vary by media type, so do not treat the 150-gallon GFO figure as the capacity for carbon or biopellets. The fittings accept 1/2-inch tubing.
Buying Guide: How To Choose A Reef Tank Reactor
What tank size should the reactor support?
Compare the manufacturer’s recommendation with your aquarium volume, and check whether the rating changes depending on the media. The PhosBan 150 is listed for tanks up to 150 gallons; the Nano model is listed for up to 75 gallons. AquaReady gives separate recommendations for GFO, carbon, and biopellets. Tank-size figures should be treated as product guidance, not as interchangeable ratings across all media.
Which media do you plan to run?
Check that the reactor is listed for your intended media. These options mention combinations of chemical media, carbon, phosphate sponges, resin-based media, GFO, or biopellets. A reactor’s media capacity and flow needs can affect which model is appropriate. Follow the media maker’s instructions when setting up and adjusting water flow.
Do you need a pump or a particular mounting style?
The AQUATOP listing includes a pump, tubing, and mount. The AquaReady is a hang-on-back model with adjustable fittings, while the Bulk Reef Supply listing highlights low-profile mounting. Confirm what is included and how the unit will connect to your aquarium before buying; not every supplied description lists pump or tubing details.
Frequently Asked Questions
What does a reef tank reactor do?
A media reactor moves aquarium water through filter media. The products listed here use up-flow designs that direct water upward through the media.
Can one reactor use different types of media?
Some listed models support multiple media types. Check the specific product details and media instructions before switching media or loading a reactor.
Is a larger reactor always better?
No. Choose based on tank volume, media type, available space, and the reactor’s stated capacity. A compact model may be a better fit for a nano tank or limited installation area.
Does every reactor include a pump?
No. The AQUATOP MR-30 listing specifically includes a pump. The supplied details for several other models do not confirm whether a pump is included.