Description
GLA PRO-CO2 Atomizing Reactor 5L
Advanced Atomizing CO₂ Reactor for Nature Aquariums
The GLA PRO-CO2 Atomizing Reactor 5L combines high-pressure CO₂ atomization with reactor-based dissolution to improve CO₂ absorption while reducing gas accumulation.
Unlike traditional reactors that rely primarily on contact time and large gas chambers, the PRO-CO2 Reactor utilizes a removable ceramic atomizer to convert CO₂ into an ultra-fine mist before it enters the reactor chamber. This dramatically increases gas-to-water contact area, helping CO₂ dissolve more rapidly and efficiently than conventional large-bubble reactor designs.
The result is improved CO₂ utilization, reduced gas accumulation, and more consistent CO₂ delivery throughout the aquarium.
Hybrid Atomizing Reactor Technology
The PRO-CO2 Reactor uses a two-stage dissolution process:
- Stage 1: High-pressure atomization creates thousands of microscopic CO₂ bubbles.
- Stage 2: The reactor chamber provides additional contact time for efficient dissolution.
Rather than relying solely on contact time, this hybrid design combines atomization and reactor-based dissolution to help maximize the amount of injected CO₂ that enters solution before water returns to the aquarium.
- Faster CO₂ dissolution
- Improved CO₂ utilization
- Reduced gas accumulation and pocketing
- More stable dissolved CO₂ concentrations
- Cleaner aquarium presentation with no visible in-tank diffuser
Improved CO₂ Utilization
The GLA PRO-CO2 Reactor is designed to help maximize the effectiveness of every bubble of CO₂ introduced into the system.
By atomizing CO₂ before it enters the reactor chamber, the system increases gas-to-water contact area and improves overall absorption efficiency.
Many aquarists can achieve target CO₂ levels while operating at lower bubble rates than conventional large-bubble reactor designs. Actual results will vary depending on aquarium size, filtration flow, circulation, plant mass, and CO₂ demand.
- Reduced CO₂ waste
- Potentially lower operating bubble rates
- Reduced gas accumulation within the reactor
- More stable CO₂ levels
- Longer intervals between CO₂ cylinder refills
By improving overall CO₂ utilization, the reactor helps make more efficient use of every CO₂ cylinder refill.
High-Pressure Ceramic Atomizing Core
At the heart of the reactor is a removable high-pressure ceramic atomizer that produces an ultra-fine CO₂ mist for rapid dissolution and improved reactor efficiency.
- Increased gas-to-water contact area
- Faster CO₂ absorption
- Reduced gas pocketing
- Improved performance across a wide range of flow rates
- Removable for cleaning and servicing
Oversized Internal Flow Path
The latest PRO-CO2 Reactor features an enlarged internal standpipe and expanded flow path designed to reduce restriction and improve water movement through the reactor.
- Larger internal standpipe
- Larger flow passages
- Reduced hydraulic restriction
- Improved flow capacity
- Enhanced compatibility with larger filtration systems
These improvements allow greater water throughput while maintaining excellent CO₂ dissolution performance.
Expanded Filter Compatibility
The reactor includes adapter sets for 12mm, 16mm, 20mm, and 1" tubing, making it suitable for a wide range of canister filters, external pumps, compact planted aquariums, and larger high-flow systems.
- 12mm Adapter Set Included
- 16mm Adapter Set Included
- 20mm Adapter Set Included
- 1" Adapter Set Included
- Compatible with many Fluval FX Series installations
Each adapter connection utilizes a clear silicone O-ring to provide a water-tight seal between the adapter and reactor lid.
High Flow Capability
The PRO-CO2 Reactor is engineered to operate across a wide range of flow rates and is particularly well suited for larger planted aquariums, high-energy aquascapes, and high-flow filtration systems.
- Minimum Recommended Flow: Approximately 300 GPH
- Typical Operating Range: 400–1200 GPH+
- Suitable for many canister filters and return pumps
- No additional power required; operates using existing filtration flow
Push-Connect CO₂ System
The reactor utilizes a push-connect CO₂ fitting and removable atomizer assembly for quick installation and simple servicing.
- Tool-free CO₂ tubing installation
- Easy atomizer removal
- Simplified maintenance
- Long-term serviceability
Serviceable Atomizer Design
Unlike permanently integrated systems, the PRO-CO2 Atomizing Reactor uses a removable ceramic atomizer assembly.
- Removable for cleaning and maintenance
- Replaceable if needed
- No need to replace the entire reactor for atomizer maintenance
Maintenance-Friendly Construction
The large reactor body and removable top allow easier inspection, access, and routine maintenance. The clear chamber also makes it easier to observe reactor operation during setup and troubleshooting.
Why Choose a CO₂ Reactor?
Many aquarium CO₂ systems lose efficiency when undissolved gas accumulates within equipment or returns to the aquarium before fully dissolving.
The GLA PRO-CO2 Reactor is engineered to maximize CO₂ absorption before water returns to the aquarium, helping provide:
- Stable CO₂ levels
- Improved plant growth potential
- Reduced CO₂ consumption
- Cleaner aquarium presentation
- No visible in-tank diffuser
- Reduced visible microbubbles in the aquarium
- No additional power required
Specifications
- Reactor Chamber Capacity: 5 Liters
- Height: Approximately 19"
- Diameter: Approximately 6"
- Minimum Recommended Flow: Approximately 300 GPH
- Typical Operating Range: 400–1200 GPH+
- Installation Location: Filter return line
- CO₂ Connection: Push-connect fitting
- Included Adapter Sizes: 12mm, 16mm, 20mm, and 1"
- Construction: Acrylic
What’s Included
- GLA PRO-CO2 Atomizing Reactor 5L with Installed High-Pressure Ceramic Atomizer
- 12mm Adapter Set
- 16mm Adapter Set
- 20mm Adapter Set
- 1" Adapter Set
- Clear Silicone O-Rings
- Installation & Maintenance Guide
Feature Highlights
- Hybrid Atomizing Reactor Technology: Combines high-pressure atomization with reactor-based dissolution.
- Improved CO₂ Utilization: Helps reduce CO₂ waste and may allow lower operating bubble rates.
- Reduced Gas Pocketing: Designed to minimize gas accumulation inside the reactor chamber.
- Removable Ceramic Atomizer: Serviceable atomizer core for easier cleaning and maintenance.
- Push-Connect CO₂ Installation: CO₂ tubing and atomizer assembly push in easily for simple setup and servicing.
- Oversized Internal Flow Path: Helps reduce restriction while supporting strong water movement.
- Expanded Filter Compatibility: Includes 12mm, 16mm, 20mm, and 1" adapter sets.
- Fluval FX Series Compatible: Designed to support many high-flow Fluval FX filter installations.
- External Installation: Keeps the aquarium clean with no visible in-tank diffuser.
- No Additional Power Required: Operates using existing filtration flow.
Frequently Asked Questions
How is this different from a traditional CO₂ reactor?
Traditional CO₂ reactors primarily rely on contact time to dissolve larger CO₂ bubbles. The GLA PRO-CO2 Atomizing Reactor first atomizes CO₂ into an ultra-fine mist before introducing it into the reactor chamber. This increases gas-to-water contact area and improves overall dissolution efficiency.
Will this reactor reduce CO₂ consumption?
Many aquarists find they can achieve target CO₂ levels while operating at lower bubble rates compared to conventional large-bubble reactor designs. Actual results will vary depending on aquarium size, flow rate, plant mass, circulation, and CO₂ setup.
Does the reactor eliminate gas pocketing?
The atomizing core is designed to significantly reduce the gas accumulation commonly associated with traditional reactor designs. Small amounts of gas accumulation may still occur depending on flow rate, CO₂ injection level, and system configuration.
Is the ceramic atomizer serviceable?
Yes. The ceramic atomizer assembly is removable for cleaning, maintenance, or replacement if needed.
What filter tubing sizes are included?
The reactor includes adapter sets for four installation sizes: 12mm, 16mm, 20mm, and 1" tubing.
Are silicone O-rings included?
Yes. Clear silicone O-rings are included for the adapter connections. Each O-ring should be properly seated beneath the adapter connection to help provide a water-tight seal between the adapter and reactor lid.
Is this compatible with Fluval FX Series filters?
Yes. The included 1" adapter set provides compatibility with many Fluval FX Series filter installations.
Where should the reactor be installed?
The reactor should be installed externally on the filter return line after the canister filter and before water returns to the aquarium.
Correct installation:
Canister Filter → PRO-CO2 Reactor → Aquarium Return
Do not install the reactor on the filter intake line.
Will I still need an in-tank diffuser?
No. The reactor is installed externally and is designed to dissolve CO₂ before water returns to the aquarium, helping maintain a clean display without a visible in-tank diffuser.
Does the reactor require additional power?
No. The reactor operates using existing filtration flow and does not require a separate pump or power source.
Can the atomizer be removed for cleaning?
Yes. The atomizer assembly can be removed for routine cleaning and servicing.
Will I see microbubbles in the aquarium?
The reactor is designed to maximize CO₂ dissolution before water returns to the aquarium. Depending on flow rate, CO₂ injection level, and aquarium configuration, some microbubbles may still be present, but many aquarists experience significantly fewer visible bubbles compared to traditional diffuser-based systems.
Do I need any tools to tighten the reactor lid screws?
No. The reactor lid screws are designed to be tightened by hand only. Do not use screwdrivers, drills, power tools, pliers, or excessive force when tightening the lid screws.
Over-tightening may damage screws, threads, seals, O-rings, or acrylic components. Tighten the screws using moderate hand pressure only.
Is a check valve included?
A check valve is recommended between the regulator and reactor to help prevent water backflow into the CO₂ system. Check valve sold separately and not included with the reactor.
Improved CO₂ Utilization. Reduced Gas Accumulation. Professional-Grade Performance.
Customer Reviews
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This is the pinnacle of what a co2 reactor should be.
3rd times the charm as the old saying goes. I’ve tried GLA’s competitors reactors and without fail they all need burping of co2 gas. I have a lot of money invested in co2 reactors and I feel I have the concept down, or you’d think by now I do. I’ve had this reactor installed almost 3 weeks, I had it dialed in by day 3 and haven’t touched my setting since. First off, this thing is huge, 5L is a big ol hunker of a reactor. The 45* elbow is very nice becouse I see zero loss of flow. But here’s where it gets interesting as I’m not sure if people understand what’s happening in the tank and it’s something I noticed on the 3rd day. You’re going to see your plants start pearling, and I mean a lot of pearling. So much that I noticed my reactor was sucking in loads of oxygen produced by plants. All that air produced by plants was going into my filter, causing nous and also injecting air into the reactor both. Although I feel most stayed inside the filter. With GLA’s tech support I simply repositioned my filter inlet a few inches away as to not be so close to the plant bed. Huge difference the next day! No kore noise from my filter having air in it and nothing going into the reactor. Plants pearling like absolute crazy is a good thing and tells me this reactor is just incredible. GLA always putting out the co2 gold!
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Much improved from an inline diffuser.
I switched from an inline because I hated the 7-Up look in my tank. I had no idea how foggy my tank was until I had co2 for a whole day. One week later and this puppy arrived and wow! My plants are pearling like never before and the view is crystal clear. I love it!
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I would buy this if you want the best co2 reactor.
Took the plunge last week and its been one awesome co2 reactor. Took me about 2 days to dial in and my plants are pearling like mad! This is a big reactor so prepare yourself. Worth every penny spent.
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One amazing co2 reactor, high quality.
Very pleased with this co2 reactor. Extremely large at 5L in volume. Minimal to no pocket of co2 with my co2 flow rate and pump, Im blown away because using other brand reactors leave a massive pocket of gas, but not this one. I see high flow exiting the reactor into the tank which pleases me because I know the reactor is not impeding my pump flow. Kudos to GLA design on this it works extremely well.
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GLA always has the best co2 equipment.
Not sure why anybody would go anywhere else for co2 gear. I remember way back in 2006 when GLA first came onto the scene. They were just 3 guys hand building everything. Always great products and service. Fast forward 20 years and these guys are still at it! It was fun talking to them when we had only forums to discuss ideas and watching them bring products nobody had ever seen before. Good to see they are still at it. This reactor is a testament to GLA’s continued efforts to bring quality co2 gear to us. I hooked this reactor up to a Hygar variable speed pump and it’s just amazing. Zero complaints at all. Zero loss of flow as well compared to my old reactor. One good thing to note is this reactor has no 90* bends anywhere. That’s plumbing 101 if you want flow to stay up to par. I just hope my cat doesn’t try to use it as a scratching post, it’s so big and I noticed my cat has taken a keen interest into it lol.
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Best co2 reactor Ive ever seen or used.
I have used countless diffusion methods mostly PVC reactors and Cerges type reactors. However this one was very intriguing so I placed my order a few weeks ago. My tank is absolutely gleaming with massive amounts of pearling. This reactor is built solid and I should stress thats its bigger than my 5lb co2 cylinder, its nice and huge! GLA provided all the hookup parts one could ever need which was very nice. I want to add, working with GLA has been a pleasurable experience in itself. They were very kind and helpful people who even held my hand at fine tuning everything. By listening to Johns insight the amount of pearling my tank experiences is mind blowing. if you are in the market for a co2 reactor I would strongly advise this jewel here. GLA knocked it out of the park with this one.
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This is the reactor if you are looking for a co2 reactor.
The photos don’t do this monster justice. I received this on Thursday and it’s now Friday night. Two days of operation and one day of fine tuning. This reactor is amazing, 100% saturation no bubbles escape. Plants are very much pearling by evening time. If you need a high quality co2 reactor, this is it my friend.
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Holy cow!
What a beast of a reactor. This thing came with all the various hose barb connections to hook up to a closed loop I made specificity for this reactor. Using a marine DC pump with controller allowed me to fine tune the flow rate going into the reactor. I’ve got a tremendous amount of pearling in my tank by 1:30/2pm . I never had that with my standard diffuser, to me that’s a game changer. I’m curious to see what adding a ph controller would do, I’ll leave that for another day though. This thing is awesome!
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GLA always has the best co2 equipment.
For decades I’ve always come to GLA for my co2 gear and essentials. After being out of the joint the last year I started back up this fall piecing my system together. I received my reactor yesterday and it’s been going now for 2 days and it’s been a treat to see my plants pearl like crazy. I never liked the 7-Up look from normal co2 diffusers, but I didn’t expect my plants to pearl so much my tank looks like 7-Up again lol. O my this time its oxygen. My Fluval FX powers the reactor and it’s absolutely beautiful. I’m looking forward to GLA figuring out a method to inject fertilizer into the reactor from my autodoser. After conversing with David at GLA he says it’s already in the works and should be ready any day. Supposed to be plug n play with the reactor so I’m really looking forward to that.
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One heck of a co2 reactor.
This is my first true co2 reactor as I come from the old Rex Grig era of pvc reactors. Using an Oase canister filter seems to work like a champ. I will say my pvc reactor was working ok but made loads of noise and started leaking which isn’t my favorite. I wanted something quieter and came to GLA to order there apparently older style acrylic reactor. Turns out it was made of plastic vs acrylic and smaller in size. I ordered this new one and installed it and so far it’s dead silent. I use an Oase skimmer on my tank to keep the surface clean and was told this will offset some of the co2 I’m injecting. Drop checker is a decent green as of 6pm today. I suspect I’ll be making adjustments as I go along. So far the quality of the build is top notch. Exactly what I see with my more expensive reef tank calcium reactor. Similar concept here all around. Really liking this unit and looking forward to see how it ages. I’d definitely recommend this reactor to anybody.
