Up to 1000 L (250 US Gal).

Fluval manufacturer warranty: 3 years, on registration with Fluval.

Compatibility

Up to 250 US Gal / 1,000 L. Fluval’s rating for the FX4, the middle of the three FX canisters.

Fluval’s published figures for the FX4 (item #A214, UPC 015561102148): pump output 700 US GPH / 2,650 LPH, filter circulation 450 US GPH / 1,700 LPH, canister volume 3.7 US Gal / 14 L, mechanical area 1,400 cm², biological volume 3.9 L / 1 US Gal, maximum head pressure 6.9 ft / 2.1 m, 30 W at both 120 V and 230–240 V, and 40 × 40 × 42 cm. Made in Italy.

Either side of it: the FX2 covers 750 L at 1,800 LPH and 27 W in a 34 × 34 × 42 cm body; the FX6 covers 1,500 L at 3,500 LPH and 43 W in a 40 × 40 × 53 cm body. The FX4 and FX6 share a footprint — the FX6 is simply 11 cm taller, which matters when you are measuring a cabinet.

The spares that fit an FX4, by Fluval item number: impeller assembly A20208, motor ring A20211, service kit A20261, AquaStop valve A20216, ribbed hosing A20236, Bio-Foam+ A239, spray bar kit A233 and the gravel vac kit A370. The FX6 uses a different impeller and seal ring (A20206 and A20207) — they are not interchangeable.

Setup & Use

Never install an FX above the water level. It is a gravity-fed system, and Fluval’s installation requirements are firm: the filter goes below the aquarium, and hosing must follow a straight path from the filter to the rim with no slack and no loops. The unit ships with 13.1 ft / 4 m of hosing. If you need to change it, Fluval’s limits are an intake run of no more than 6.5 ft / 2 m and a combined intake-plus-outlet length of no more than 16.4 ft / 5 m.

The filter primes itself, and the pause is normal. As soon as an FX is plugged in, Smart Pump begins its priming sequence: the pump runs for one minute to fill the canister with aquarium water, stops for two minutes to evacuate air, then restarts and runs continuously. That sequence repeats every time the unit is unplugged and plugged back in. Every twelve hours thereafter the pump stops for one minute to evacuate any air that has collected inside. A new owner who has not read this reliably thinks the filter has failed.

How the water actually moves through it. Fluval’s own description: water first moves to the bottom of the canister, rises to the top through the foam pads, then passes back down through the media trays in the middle before returning to the aquarium. Knowing the direction is what tells you which basket to fill with mechanical media and which to keep for biological.

Draining an FX4 for service. Fluval’s sequence: close the IN and OUT valves in order, unplug the pump, take the utility hose out of the lid clips and point it at a drain, then open the utility valve anti-clockwise and disconnect the OUT valve. The canister drains by gravity until it equalises with the drain, and you pour out the rest. This is the reason the utility valve exists — you never lift a full canister.

Fluval’s maintenance frequency chart for the FX series:

Magnetic impeller — check and clean every 3 months, replace yearly
Motor seal ring — check and clean every 3 months, replace yearly
Intake stem and strainer — check and clean every 3 months
Ribbed hosing — check and clean every 6 months
Bio-Foam — check and clean monthly, replace half the quantity every 6 months
Bio-Foam+ — check and clean every 3 months, replace every 6 months
BIOMAX — rinse monthly, replace half the quantity every 6 months
Carbon pad — replace monthly
Inside of the canister — check and clean monthly

Fluval add that skipping this invalidates the warranty, and that air trapped during a service can flush settled dirt back into the tank if the canister interior has been neglected.

Never change all the media at once. Fluval repeat this in every manual: the beneficial bacteria live on the media, so staggering replacement is what keeps the biological filter alive through a service. Rinse media in water taken out of the aquarium — never under the tap, and never with soap or detergent.

Safety & Precautions

Unplug everything in the tank before your hands go in the water. That is Fluval’s own instruction and it covers every appliance in the aquarium, not just this one. Grasp the plug and pull it; never yank the cord.

Indoor, domestic, ornamental aquariums only, and never above 35 °C. Fluval rate this as a non-submersible aquarium filter-pump for household use in fresh or salt water, with a maximum water temperature of 35 °C. It is not for ponds, swimming pools or bathrooms, must not be stored where it will meet weather or freezing temperatures, and must not be run dry. The 35 °C ceiling is worth remembering here — a closed room through an Indian summer can take an uncooled tank close to it.

Arrange a drip loop. Fluval ask you to position the appliance to one side of a wall socket and leave a loop of cable hanging below the socket, so water running down the cord drips off before it reaches the outlet. If the plug or socket does get wet, do not pull the plug — kill the circuit at the breaker first, then unplug and inspect.

The power cord cannot be replaced. Fluval state this plainly: if the cord is damaged the appliance must be discarded, and the cord must never be cut. There is no repair for it, here or anywhere. The same goes for a unit that has been dropped, is malfunctioning, or shows abnormal leakage — Fluval’s instruction is to stop using it rather than open it up.

Do not attempt repairs yourself. Fluval’s instruction is to return the appliance to an authorised service facility or discard it. If it falls into the water, do not reach for it — unplug at the wall first. If it leaks or trips an RCD, disconnect it from the mains.

Silicone lubricant only. Fluval are explicit about this in both the 07 Series and FX manuals: seals and O-rings are lubricated with a silicone-based lubricant only, and they name their own Fluval Silicone Lubricant (item #A325). Petroleum jelly and vegetable- or animal-based products are not to be used, and Fluval say that using anything else voids the guarantee.

Fluval’s note on children: the appliance may be used by children aged 8 and above, and by people with reduced physical, sensory or mental capability, only under supervision or instruction. Children are not to play with it, and cleaning and user maintenance are not to be done by children unsupervised.

Warranty & Support

This product carries a 3-year manufacturer warranty from the date of purchase against defects in material and workmanship, which Fluval extends to 5 years free of charge if you register the product.

Warranty support is handled by us directly. Message our WhatsApp support with your order number and we will diagnose the fault first. Most cases are solved by replacing a single part, so you rarely need to send the whole unit. If the item does need to come back, it ships to our Delhi or Pune warehouse, whichever one served your order, and courier cost in both directions is borne by the customer. Your GST invoice is valid proof of purchase for the claim.

Returns & Replacement

Returns are accepted within 7 days of delivery, provided the item is unused and in its original packaging. Manufacturer-sealed items cannot be returned once the seal is broken, and sale-priced items are not refundable.

If your item arrives defective or damaged, message us on WhatsApp with your order number, or email us if you would rather, and we will replace it. Approved replacements are delivered within 3 to 5 business days. Transit damage is covered by insurance on every shipment. If tracking shows delivered but nothing reached you, tell us within 72 hours, which is the reporting window Indian couriers allow. Damage caused during installation or use is not covered; replacement spares for such cases are chargeable.

Full terms are on our Cancellation & Returns page.