Fluval U Clean & Clear Cartridge
Water type
Freshwater + Marine + Reptile/paludarium
Fits
Fluval U1 internal filter, Fluval U2 internal filter, Fluval U3 internal filter, Fluval U4 internal filter
Media type
Phosphate- and nitrate-reducing resin cartridge
Fluval U Clean & Clear Cartridge
Polishes the water in a Fluval U filter without adding a second cartridge. The Clean & Clear cartridge uses a resin media that reduces phosphate and nitrate, fitted into the central cartridge position alongside the BIOMAX biological media already supplied with the filter. It's an optional upgrade for anyone whose Fluval U is running clear on the mechanical stage but still testing high on nutrients.
Will it fit my filter?
Yes, if you run any Fluval U internal filter – U1, U2, U3 or U4. It's a universal fit across the whole U-series range, so you don't need to match it to a specific model or size.
Key features
- Reduces phosphate and nitrate – targets the two nutrients most responsible for algae flare-ups, on top of the filter's normal mechanical and biological stages.
- Fits all four U-series sizes – one cartridge works across U1, U2, U3 and U4.
- Drops straight into the existing cartridge slot – no extra basket or plumbing, works alongside the BIOMAX media already in the filter.
Specifications
| Field | Details |
|---|---|
| Fits | Fluval U1, U2, U3 and U4 internal filters – universal fit across the whole U-series |
| Manufacturer part number | PF136 |
| Media type | High-performance resin blend targeting phosphate and nitrate |
| Removes / provides | Phosphate and nitrate reduction; fits alongside the filter's existing foam pad and BIOMAX biological media, not a replacement for either |
| Water type | Freshwater, marine and reptile/paludarium – matches the Fluval U-series filter range |
| Replacement interval | Not published by Fluval – check phosphate/nitrate test results every 4 to 6 weeks and replace once readings stop improving after a water change |
What's included, and what you'll still need
The pack contains the resin cartridge only. It's an addition to your Fluval U's existing foam pad and BIOMAX media, not a replacement for either – keep both in place when you fit this cartridge.
Suitable for, and not suitable for
Suitable for freshwater, marine and reptile/paludarium setups running a Fluval U filter. Not a substitute for regular water changes – resin media slows nutrient build-up, it doesn't remove the need for maintenance.
Care and maintenance
Fluval does not publish a fixed replacement interval for this cartridge. As a general guide, check your phosphate and nitrate test results every 4 to 6 weeks and replace the cartridge once readings stop improving after a water change.
Warranty and delivery
This is a consumable filter media, used until exhausted rather than covered under a mechanical warranty. Standard parcel delivery.
Common questions
Does this replace the foam pad or BIOMAX media in my Fluval U?
No. It fits alongside them in the central cartridge position – keep the foam pad and BIOMAX in place.
Do I need a different size for a U1 versus a U4?
No. This cartridge is a universal fit across all four Fluval U sizes.
Will this cartridge clear cloudy water?
It's built for phosphate and nitrate reduction rather than mechanical clarity. Cloudy water from suspended particles is better addressed by the filter's foam pad and, if needed, a finer polishing pad.
