Made by Think Crucial
6 Bio-Foam Filters for Fluval FX4, FX5 & FX6
Shipping
Free U.S. shipping on every order
Dispatch
Ships same business day when ordered by 2pm ET
Fit
Fit guaranteed on the models listed
Returns
30-day returns
Check your model.
Type what's printed on your unit's rating label. Only models we've listed come back as a fit.
Fits these models 3 listed
- Fluval FX4✓ Listed
- Fluval FX5✓ Listed
- Fluval FX6✓ Listed
Don't see your model? Compatibility not confirmed. Email support@thinkcrucial.com with the model number from the label before you order, and we'll tell you whether this fits.
It's on the rating label. Check the back, the base, or inside the filter door, and type the MODEL NO. line exactly as printed. The drawing is a guide; your label may sit elsewhere.
Brand and model names are used only to show compatibility. Think Crucial is an independent brand, not affiliated with those manufacturers.
What's in the box.
Exactly what ships, so you can match it against what's in your machine now.
In the box1 line
- 6 x bio-foam filter pads
- Fits
- Fluval FX4, Fluval FX5, Fluval FX6
- Fits
- Fluval FX4, FX5, FX6
- Pack
- 6 foam pads
- Stage
- Biological filtration
- Made by
- Think Crucial (aftermarket, not affiliated with Fluval)
Think Crucial vs. Fluval's own.
We only quote the other brand's price once we've checked it and can show you where.
| What | Think Crucial | Fluval's own filter |
|---|---|---|
| Fits the models listed | Yes, listed and fit-guaranteed | Yes |
| Price | $25.34 with free U.S. shipping | Not quoted |
| If it doesn't fit | Prepaid return label, full refund, 30 days | Fluval's own terms |
| Made by | Think Crucial | Fluval |
Aftermarket means we make the part to fit the models listed. It isn't made by or affiliated with Fluval. You get the same job done with our own build, and our fit guarantee on top.
What owners say.
On thinkcrucial.com
No reviews of this filter on thinkcrucial.com yet. Bought one? Tell the next person whether it fit and how it's doing.
Write the first review
Before you order.
Shipping, returns and fit work the same on every product.
Q01Will it fit my machine?
It's listed for Fluval FX4, Fluval FX5, Fluval FX6. If your label shows a different model, compatibility isn't confirmed: email support@thinkcrucial.com with the model number before you order. If a listed model doesn't fit, we send a prepaid return label and refund you in full.
Q02Is this an original Fluval part?
No. It's an aftermarket filter made by Think Crucial to fit the models listed. Think Crucial is not affiliated with Fluval. We make what we sell.
Q03What if it doesn't fit, or I change my mind?
If it doesn't fit the model we list, we email a prepaid return label within 30 days of delivery and refund you in full; opened to test the fit is fine. Changed your mind? Return it unused in its original packaging within 30 days of delivery. The return label is free for these too.
Q04When will it arrive?
Shipping to U.S. addresses is free on every order. It ships the same business day when you order by 2pm ET, and arrives in 2–5 business days.
Q05Is there a subscription?
No. You buy one when you need one. Nothing renews and nothing auto-ships.
We make what we sell.
Think Crucial started in 2007 at a family vacuum repair shop. Today we make aftermarket filters, bags and parts built to fit the machines you already own, plus our own descalers and cleaners. Most people can fit the part themselves. They just need the right one, and a way to check it first.
- Find the model number on the rating label
- Match it to the list on this page
- Not listed? Ask us before you order
Ready to order
6 Bio-Foam Filters for Fluval FX4, FX5 & FX6
Fits 3 Fluval models
$25.34Free U.S. shipping
Fit guaranteed: prepaid return label if it doesn't fit the model we list. 30-day returns.
Full product description
A 6-pack of replacement bio-foam pads for Fluval FX4, FX5 and FX6 canister filters. The foam gives beneficial bacteria a place to grow, which is the biological stage of your filter that breaks down ammonia and nitrite.
Fits
Fluval FX4, FX5 and FX6 canister filters.
What's in the box
6 bio-foam filter pads.
What if it doesn't fit?
30-day returns. If it doesn't fit a model we list, we send a prepaid return label.
Designed and engineered in the USA by Think Crucial. Think Crucial is an independent brand and is not affiliated with Fluval. Brand and model names are used only to show compatibility. This is not a Fluval part and is not covered by a Fluval warranty.
Brand and model names are used only to show compatibility. Think Crucial is an independent brand, not affiliated with those manufacturers.