When it comes to aquarium filtration, few names are as widely recognised as Fluval. Trusted by fishkeepers around the world, Fluval external filters have earned a reputation for reliability, powerful filtration, user-friendly maintenance, and long-term performance.
Whether you’re setting up your first external filter, maintaining an established aquarium, or troubleshooting a problem, this guide covers everything you need to know about Fluval external filters.
Why Choose a Fluval External Filter?
External canister filters offer several advantages over internal filters, including increased filtration capacity, improved water quality, and a cleaner appearance inside the aquarium.
Fluval external filters are particularly popular because they offer:
- Large biological filtration capacity
- Excellent mechanical filtration
- Quiet operation
- Easy maintenance
- Reliable performance
- Wide range of sizes for different aquarium setups
From small tropical aquariums to large community tanks and cichlid systems, there is a Fluval filter suitable for almost every freshwater and marine aquarium.
Understanding the Fluval Filter Range
Fluval 07 Series
The 07 Series represents Fluval’s most popular range of external filters and includes:
- Fluval 107
- Fluval 207
- Fluval 307
- Fluval 407
These models feature improved energy efficiency, quieter motors, stronger seals, and redesigned media baskets compared to previous generations.
Which Fluval 07 Filter Do You Need?
Fluval 107
Ideal for aquariums up to approximately 130 litres.
Perfect for:
- Nano aquariums
- Small community tanks
- Shrimp aquariums
Fluval 207
Ideal for aquariums up to approximately 220 litres.
Perfect for:
- Tropical community tanks
- Planted aquariums
- Medium-sized freshwater setups
Fluval 307
Ideal for aquariums up to approximately 330 litres.
Perfect for:
- Larger planted aquariums
- Community aquariums
- Heavily stocked freshwater tanks
Fluval 407
Ideal for aquariums up to approximately 500 litres.
Perfect for:
- Large freshwater aquariums
- African cichlid setups
- Predator fish tanks
- Large community aquariums
Fluval FX Series
The Fluval FX range is designed for larger aquariums requiring maximum filtration performance.
Popular models include:
- Fluval FX2
- Fluval FX4
- Fluval FX6
These filters feature:
- Massive media capacity
- High flow rates
- Self-priming technology
- Automatic air evacuation systems
- Powerful mechanical filtration
The FX Series is widely considered one of the best choices for heavily stocked freshwater systems.
How Fluval External Filters Work
Fluval filters use a multi-stage filtration process.
Mechanical Filtration
Mechanical media removes physical debris from the water.
Examples include:
- Foam blocks
- Filter floss
- Polishing pads
This stage helps keep water crystal clear.
Biological Filtration
Biological media provides a home for beneficial bacteria that convert harmful ammonia and nitrite into less harmful nitrate.
Popular Fluval biological media includes:
- BioMax
- Bio-Foam
- Ceramic rings
This stage is the most important part of the filtration process.
Chemical Filtration
Chemical media removes dissolved pollutants from the water.
Common options include:
- Activated carbon
- Phosphate removers
- Purigen
- Specialty resins
Not every aquarium requires chemical filtration at all times.
How to Set Up a Fluval External Filter
Step 1: Assemble the Media
Arrange media in the correct order:
- Mechanical filtration first
- Biological filtration second
- Chemical filtration last
This ensures debris is removed before water reaches your biological media.
Step 2: Install Intake and Return Pipes
Position the intake and outlet at opposite ends of the aquarium where possible.
This helps maximise circulation throughout the tank.
Step 3: Fill and Prime the Filter
Use the Fluval AquaStop valves and priming system according to the manufacturer’s instructions.
Most Fluval filters can be primed with only a few pumps of the priming handle.
Step 4: Check for Leaks
Before leaving the filter unattended:
- Check hose connections
- Inspect O-rings
- Confirm valves are fully open
How Often Should You Clean a Fluval Filter?
Maintenance frequency depends on stocking levels and aquarium type.
As a general guide:
Every 2–4 Weeks
- Clean intake strainers
- Check hoses for debris
- Clean pre-filter sponges
Every 4–8 Weeks
- Clean mechanical filter media
- Remove accumulated sludge
Every 3–6 Months
- Inspect impeller assembly
- Clean impeller chamber
- Check seals and O-rings
Important
Never replace all biological media at the same time. Doing so can remove beneficial bacteria and destabilise your aquarium.
Common Fluval Filter Problems and Solutions
Reduced Water Flow
Possible causes:
- Dirty media
- Blocked intake
- Dirty hoses
- Impeller buildup
Solution:
Perform a full filter maintenance and clean all flow paths.
Noisy Operation
Possible causes:
- Air trapped in the filter
- Dirty impeller
- Worn impeller shaft
Solution:
Clean the impeller assembly and ensure all trapped air has been removed.
Leaking Filter
Possible causes:
- Damaged O-ring
- Dirty sealing surfaces
- Incorrectly seated gasket
Solution:
Clean and lubricate O-rings using aquarium-safe silicone lubricant.
Filter Won’t Prime
Possible causes:
- Closed valves
- Airlock in hoses
- Incorrect hose installation
Solution:
Check all valves and ensure hoses are fully filled with water.
Best Media Upgrades for Fluval Filters
Many hobbyists customise their Fluval media setup for improved performance.
Popular upgrades include:
Seachem Matrix
Provides extremely high biological filtration capacity.
Purigen
Helps improve water clarity and reduce dissolved organics.
Fine Filter Floss
Produces crystal-clear water by trapping fine particles.
Phosphate Removal Media
Useful in aquariums suffering from algae problems.
Tips for Maximising Fluval Filter Performance
- Avoid over-cleaning biological media.
- Use high-quality biological filtration media.
- Clean hoses regularly.
- Replace worn impellers promptly.
- Avoid overcrowding your aquarium.
- Perform regular water changes.
- Keep intake strainers free from debris.
Frequently Asked Questions
Can Fluval Filters Be Used on Marine Aquariums?
Yes. Many Fluval external filters are used successfully on marine fish-only and reef aquariums, particularly for chemical filtration and water polishing.
Should I Run Carbon All the Time?
Not necessarily. Many aquarists use activated carbon periodically rather than continuously.
How Long Does Fluval BioMax Last?
BioMax can last for many years if cleaned properly and not allowed to become clogged.
Are Fluval Filters Energy Efficient?
Yes. The latest 07 Series filters are significantly more energy-efficient than previous generations while maintaining excellent performance.
Final Thoughts
Fluval external filters have become a trusted choice for aquarists thanks to their reliability, performance, and ease of maintenance. Whether you choose a compact Fluval 107 for a community aquarium or a powerful FX6 for a large freshwater setup, proper installation and maintenance will help ensure years of trouble-free operation.
At Charterhouse Aquatics, we stock the complete range of Fluval external filters, replacement parts, media, hoses, impellers, and accessories. If you’re unsure which Fluval filter is right for your aquarium, our experienced team is always happy to help.
