Fluval FX4 Service Kit

This genuine Fluval FX4 Service Kit includes the impeller assembly, seals, and O-rings needed for routine canister filter maintenance.

Compatibility:

The Fluval FX4 Service Kit is a replacement part for keeping your filter running at full performance — see our guide to choosing filter media for how media and hardware work together in a filtration system.

Specifications

Fluval item #A20261, UPC 015561302616. The service kit for the FX4 canister filter, made up of four separately numbered Fluval parts: the magnetic impeller assembly (A20208), the motor seal ring (A20211), four top-cover click-fit O-rings (A20212) and the filter lid O-ring (A20210).

Every wearing part in the pump and lid, in other words, in one box — which is the point of buying a kit rather than four line items.

Compatibility

FX4 canister filter only. Fluval's own compatibility statement for A20261. The FX2 kit is A20264 and the FX6 kit is A20259.

The FX2 and FX4 share an impeller (A20208) and a motor ring (A20211); what separates the two kits is the lid O-ring — A20210 here, A20213 on the FX2. The FX6 kit differs more substantially: a larger impeller assembly (A20206, with bushing and bushing tool) and a different seal ring (A20207).

Setup & Use

The kit exists because Fluval's schedule replaces all of it on the same clock. On their FX maintenance chart the magnetic impeller and the motor seal ring are both checked and cleaned every three months and replaced yearly. Doing them together, once a year, is the intended service.

Close the valves, unplug, then drain. Before any part of a canister filter comes off, Fluval's sequence is: turn the IN and OUT valves to the closed (horizontal) position, unplug the pump, then disconnect. The canister sits below the tank and is full of water — opening it in the wrong order empties it onto the floor, and on an FX4 or FX6 that is fourteen to twenty litres.

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 warning about the canister interior applies here too. If the inside of the canister has not been cleaned on their monthly schedule, air trapped during a service can flush settled dirt straight back into the tank when you restart. Clean the canister while it is open.

Safety & Precautions

Close the valves, unplug, then drain. Before any part of a canister filter comes off, Fluval's sequence is: turn the IN and OUT valves to the closed (horizontal) position, unplug the pump, then disconnect. The canister sits below the tank and is full of water — opening it in the wrong order empties it onto the floor, and on an FX4 or FX6 that is fourteen to twenty litres.

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.

A spare is only as safe as the unit it goes into. Fluval's standing instructions still apply to the filter itself: the power cord cannot be replaced or cut, a unit that has been dropped or shows abnormal leakage should not be put back into service, and repairs go to an authorised service facility rather than a kitchen table.

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.