Fluval AC20/30 Biomax Insert 42gm
Suits tanks
18–114 L
Water type
Freshwater + Marine
Fits
Fluval AquaClear 20, Fluval AquaClear 30
Part no.
19660
Replace every
3 months
Fluval AC20/30 Biomax Insert 42gm
Extra surface area for the bacteria that break down waste.
Fluval's Biomax insert for the AquaClear 20 and AquaClear 30, 42 g, is the biological stage of the AC20/30 media basket. Its porous rings spread water flow evenly and hold it in contact longer, giving nitrifying bacteria more surface to establish on than an empty basket ever could. It suits any AC20 or AC30 owner topping up or replacing the biological media that came with the filter.
Key features
- Porous ring design — increases contact time between water and the bacterial colony living on the media.
- Fits AC20 and AC30 — one 42 g insert, sized for the top-front section of either basket.
- Fresh and saltwater safe — the same insert works across both water types.
- Rinseable, not disposable on a fixed schedule — cleaned in place rather than replaced every month.
Specifications
| Fluval item | 19660 |
|---|---|
| Weight | 42 g |
| Fits | AquaClear 20, AquaClear 30 power filters |
| Water type | Freshwater and saltwater |
| Position in basket | Top front section |
Will it fit my filter?
| Filter | Aquarium size | Flow rate |
|---|---|---|
| AquaClear 20 | 18–76 L | 379 L/h |
| AquaClear 30 | 38–114 L | 568 L/h |
This is the 42 g size used across both the AC20 and AC30 baskets. The AquaClear 50 takes a larger 125 g insert and the AC70 a 195 g insert — check your filter's model number before ordering a replacement.
Suitable for, and not suitable for
Suitable for topping up or replacing Biomax in an AC20 or AC30 basket, freshwater or marine. Not suitable for the AC50, 70 or 110 baskets, which need a larger insert.
Care and maintenance
Rinse before first use. Fluval's own maintenance schedule for the AC series calls for a rinse roughly every two months and a full replacement around every three — sooner in a heavily stocked tank, since a clogged pore structure stops carrying the bacterial load it's designed for.
Goes well with
- Clear-Carb Insert — the chemical stage that sits alongside Biomax in the same basket
- Bio-Foam Insert — the mechanical stage underneath
Warranty and delivery
Sold as genuine Fluval filter media. Your rights under the Australian Consumer Law apply in full and nothing here limits them. Ships as a standard small parcel anywhere in Australia.
Common questions
Is this ceramic media?
Fluval doesn't publish the exact material on this insert, so we don't state a composition we can't confirm. It's described as a porous ring media designed for biological filtration.
Do I rinse it in tap water or tank water?
Fluval's manual says to rinse thoroughly without specifying the water source. Many keepers use removed tank water to avoid killing off the bacterial colony with chlorinated tap water.
Does the same insert fit the AquaClear 50?
No. The AC50 uses a larger 125 g Biomax insert. This 42 g size is for the AC20 and AC30 only.
How often does it need replacing?
Fluval's maintenance chart suggests rinsing around every two months and replacing around every three, though a heavily stocked tank may need it sooner.
Can I use it in a saltwater tank?
Yes. This insert is listed for both freshwater and saltwater AquaClear 20/30 filters.
