Fluval FX Super Filter
Water type
Freshwater + Marine
Warranty
3 years
Fluval FX Super Filter
One canister range, three flow rates, sized to the tank rather than the other way round. The Fluval FX Super Filter is Fluval's high-output external canister range, sold here as the FX2, FX4 and FX6 — external canister filters rated for aquariums up to 750 L, 1000 L and 1500 L respectively. All three share the same self-priming Smart Pump, multi-stage mechanical/biological/chemical media and lift-out basket design; they differ in motor output, media volume and physical size. This page covers all three so you can compare them side by side rather than guess from the litres-per-hour number alone.
Key features
- Self-priming Smart Pump — fill with water, plug in, and the pump starts itself. No manual priming.
- Auto air evacuation — trapped air is purged automatically roughly every 12 hours, so flow doesn't quietly drop off between services.
- Multi-stage filtration — mechanical, biological and chemical media included across all three sizes.
- Lift-out media baskets — media stays contained and comes out as a stack rather than loose handfuls.
- Compact, under-tank footprint — a similar 40 x 40 cm base across FX4 and FX6, with FX2 slightly smaller at 34 x 34 cm.
- Fresh and marine safe — the same range suits both, media choice permitting.
Specifications
| Spec | FX2 | FX4 | FX6 |
|---|---|---|---|
| Aquarium size | Up to 750 L | Up to 1000 L | Up to 1500 L |
| Pump output (unrestricted) | 1800 L/h | 2650 L/h | 3500 L/h |
| Filtered circulation (media loaded) | 1300 L/h | 1700 L/h | 2130 L/h |
| Max head height | 2.1 m | 2.1 m | 3.3 m |
| Wattage (120 V or 230–240 V) | 27 W | 30 W | 43 W |
| Canister volume | 10.6 L | 14 L | 20 L |
| Dimensions (L x W x H) | 34 x 34 x 42 cm | 40 x 40 x 42 cm | 40 x 40 x 53 cm |
| SKU | AA2955 | AA0556 | AA0557 |
Media basket volume is published inconsistently across the range: Fluval states 3.9 L total for the FX2 and 5.9 L for the FX6, but only lists a 3.9 L biological compartment for the FX4 rather than a total figure — we haven't published an FX4 total media volume for that reason, rather than guess at it.
Performance — flow against head
The single litres-per-hour figure printed on the box is measured with nothing attached — no hose, no media, no lift. Two more useful numbers from Fluval's own spec sheets: the flow rate once media is loaded and water is actually being filtered, and the head height at which the pump stops moving water altogether. Fluval does not publish the intermediate points of the curve between those two figures, so we're showing what's published rather than interpolating a smooth line.
| Model | Pump output, no restriction | Filtered flow, media loaded | Flow at max head |
|---|---|---|---|
| FX2 | 1800 L/h | 1300 L/h | 0 L/h at 2.1 m |
| FX4 | 2650 L/h | 1700 L/h | 0 L/h at 2.1 m |
| FX6 | 3500 L/h | 2130 L/h | 0 L/h at 3.3 m |
In practice, expect actual circulation closer to the "filtered flow, media loaded" column once the canister is running with sump-style plumbing, elbows and a realistic lift — not the headline pump output.
Which one do I need?
Match the filter to your stocked tank volume, not just the tank's rated capacity — a heavily stocked tank benefits from sizing up.
| FX2 | FX4 | FX6 | |
|---|---|---|---|
| Best for | Tanks up to roughly 750 L, lightly to moderately stocked | Tanks up to roughly 1000 L, or a smaller heavily stocked tank | Tanks up to roughly 1500 L, or multi-tank systems needing high turnover |
| Step up if | Approaching 750 L or adding bioload | Approaching 1000 L or adding bioload | — |
What's included
Each size ships with the canister body, motor head, all media baskets, a full set of mechanical, chemical and biological media, intake and spray bar assemblies, and the hoses needed for a standard installation.
Not included
None of the three sizes include the FX Gravel Cleaner Kit or replacement vacuum bags — these are sold separately and only fit the FX4 and FX6 (2nd generation).
Running costs and noise
| Model | Wattage | Running 24/7 | Indicative annual cost* |
|---|---|---|---|
| FX2 | 27 W | ≈236.5 kWh/year | ≈$70.96/year |
| FX4 | 30 W | ≈262.8 kWh/year | ≈$78.84/year |
| FX6 | 43 W | ≈376.7 kWh/year | ≈$113.00/year |
*Calculated at 30c/kWh assuming continuous 24-hour operation, which is how a canister filter is normally run. Fluval does not publish a decibel rating for this range, so a noise figure isn't shown here rather than estimated.
Suitable for, and not suitable for
Suitable for freshwater and marine tanks within each model's rated volume, and for stands or cabinets with room for a unit up to 53 cm tall (FX6). Not suitable as the sole filtration on a heavily stocked tank near or above the top of its rated range — step up a size rather than run one filter flat out.
Warranty and delivery
3 year limited warranty against manufacturing defects, in addition to your rights under Australian Consumer Law. 230–240 V / 50 Hz, Australian plug. Standard parcel freight — no special handling required.
Goes well with
- Fluval FX Gravel Cleaner Kit — connects to the FX4 and FX6 utility valve for vacuum-through-filter water changes.
- Fluval FX Service Kit (A20259) — impeller and seal spares for the FX5/FX6 motor (FX6 owners only; FX4 uses different service parts).
Common questions
Is the litres-per-hour number on the box what I'll actually get?
No. That figure is the unrestricted pump output with nothing attached. Once media, hoses and a realistic lift are in place, expect flow closer to the "filtered flow, media loaded" figure in the table above.
Which size do I need for a 1000 L tank?
The FX4 is rated to 1000 L. If the tank is heavily stocked, or you're running it near the top of that range, the FX6 gives more headroom.
Can I run this on a marine or reef tank?
Yes, all three sizes are fresh and marine safe.
Does the FX2 fit the same gravel vacuum kit as the FX4 and FX6?
No. The Fluval FX Gravel Cleaner Kit is built for the FX4 and FX6 (2nd generation) utility valve only, and isn't listed as compatible with the FX2.
How loud is it?
Fluval hasn't published a decibel figure for this range, so we're not quoting one — in general, canister filters in this class run quietly under normal operation with no trapped air.
