Fluval FX6
#1 in Over 150 galFull review
The flow king for very large tanks, at the lowest cost per rated gallon. Many owners pair it with a second filter on tanks near its rating.
Amazon $406.99$406.99
Up to 400 gal925 gal/h5.9 L
3.4/5
A powerful, efficient filter for big tanks, with a handy water-change valve. Treat the 250 gallon rating as generous and size by media need.
- Up to 250 galTank size
- 700 gal/hFlow
- 3.9 LMedia
- 30 WPower
Check price at Amazon$337.99
Price checked November 9, 2026. As an Amazon Associate we earn from qualifying purchases.
Pros
- Pumps 700 gal/h on 30 W, the most efficient pump here
- Built-in valve drains the canister and runs water changes
- Self-starting, no priming needed
Cons
- Same 3.9 L of basket space as the smaller FX2, light for a 250 gallon rating
The Fluval FX Series family
Every Fluval FX Series model we rank, smallest first. Ratings compare each against its own tank size.
| Model | Tank size | Rating | Price |
|---|---|---|---|
| Fluval FX2 | Up to 175 gal | 3.2/5 | $296.99 |
| Fluval FX4 (this one) | Up to 250 gal | 3.4/5 | $337.99 |
| Fluval FX6 | Up to 400 gal | 3.4/5 | $406.99 |
How it scores
The rating comes from 6 measured or published factors, each scored 0-100 against fixed reference points for its tank size. How we rank explains each one.
Specifications
| Model number | A214 |
|---|---|
| Capacity | |
| Rated aquarium | Up to 250 gal |
| Pump output | 700 gal/h |
| Filter circulation | 450 gal/h |
| Turnover | 2.8x per hour |
| Max head height | 6.9 ft |
| Media | |
| Media volume | 3.9 L |
| Canister volume | 14 L |
| Features | |
| Primer | Yes |
| Shutoff valves | Yes |
| Built-in UV | No |
| Built-in heater | No |
| Water-change valve | Yes |
| Power and build | |
| Power draw | 30 W |
| Warranty | 3 years |
Alternatives in this tank size
EHEIM Professionel 4+ 600
#2 in Over 150 galFull review
A premium square canister for tanks up to 160 gallons, with lots of media and thoughtful maintenance features.
Amazon $329.99$329.99
Up to 160 gal330 gal/h6.5 L
OASE BioMaster 2 600
#4 in Over 150 galFull review
A media-heavy filter for tanks up to 160 gallons, for owners who value biological capacity over raw flow.
Amazon $334.99$334.99
Up to 160 gal350 gal/h6.8 L
Compare
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