Fluval Bio Foam Replacement (2 pack)
Pack size
2-pack
Water type
Freshwater + Marine
Fits
Fluval U2, Fluval U3, Fluval U4
Fluval Bio Foam Replacement (2 pack)
Fresh bio-foam brings a tired U-Series filter back to full mechanical and biological filtration. Genuine Fluval Bio-Foam pads, sold as a pack of two, sized to the U2, U3 or U4 underwater filter — pick the model printed on your filter housing, not your tank size, since the wrong pack simply won't seat.
Key features
- Genuine Fluval foam — traps suspended debris and hosts the beneficial bacteria that do your biological filtration.
- Two pads per pack — a full media change for one filter.
- Model-specific fit — cut to the exact housing size of the U2, U3 or U4, no trimming.
- Reusable housing, replaceable foam — only the worn foam needs changing, not the filter body.
Specifications
| Attribute | Detail |
|---|---|
| Pack quantity | 2 pads |
| Media type | Bio-Foam — mechanical and biological foam |
| Fits | Fluval U2, U3 or U4 internal filters (model sold separately by variant) |
| Water type | Freshwater and saltwater |
Which model do I need?
| Variant | Genuine part number | Fits filter | Filter suits aquariums up to |
|---|---|---|---|
| U2 | A486 | Fluval U2 internal filter | 30 US gal / 110 L |
| U3 | A487 | Fluval U3 internal filter | 40 US gal / 150 L |
| U4 | A488 | Fluval U4 internal filter | 65 US gal / 240 L |
Check the model number moulded into your filter body or printed on the box — U2, U3 and U4 foam is not interchangeable between models.
Suitable for, and not suitable for
- Suitable for the Fluval U2, U3 and U4 underwater filters, freshwater or saltwater.
- Not suitable for the smaller U1, or for Fluval's canister (06/07-series) or Nano filters — those take different foam entirely.
Care and maintenance
Rinse in removed tank water, never tap water, to protect the bacteria colony, and replace once the foam stays compressed after squeezing or debris no longer rinses free. Stagger the change against any carbon or Bio-Max media in the same housing.
Goes well with
Servicing the rest of the filter at the same time? The Fluval Filter Bracket for U2/U3 and Fluval U2 Internal Filter Impeller Assembly cover the other parts that wear on the same filter.
Warranty and delivery
As a consumable filter media, this pad is a wear item and sits outside Fluval's equipment warranty — your rights under Australian Consumer Law apply regardless. Standard parcel delivery.
Common questions
How do I know if I have a U2, U3 or U4?
The model is moulded into the filter housing and printed on the original box. It doesn't correspond directly to tank size if you've since changed tanks, so check the filter itself.
Can I fit U3 foam into a U2 housing?
No — each model's foam is cut to that housing only and won't seat properly in a different size.
How often should I replace the foam?
Fluval doesn't publish a fixed interval for this pad — replace it once it stays compressed after squeezing, debris no longer rinses free, or flow through the filter has visibly dropped.
Will it work in a saltwater tank?
Yes — the foam is inert and suits freshwater and saltwater systems equally.
