Fluval Aquaclear Hang on Filter AC20 379lph

• Adjustable flow control – the intake strainer has a built-in flow lever, so you can wind the AC20 back for bettas, shrimp or fry without buying a smaller filter.
• Refillable media basket – foam, activated carbon and BioMax ceramic rings sit in one basket you lift out as a unit, rather than a sealed cartridge you throw away.
• Three-stage filtration – mechanical (foam), chemical (carbon) and biological (BioMax) media in the one pass.
• Large surface area for a nano filter – the AquaClear media basket is sized generously for a filter this small, which is why it's a common upgrade pick for 20-40 L tanks running stock cartridge filters.
• Fresh and marine safe – rated for both freshwater and saltwater use, up to 35°C.

The AC20 is rated to 18-76 L. As a rough guide, that covers most nano and small tanks up to about 60 cm long, provided the glass or acrylic rim is no thicker than 2.4 cm where the filter hangs. If your tank sits above 76 L, or your bioload is heavy for its size, step up to the AC30 below rather than running the AC20 at its ceiling.

All five AquaClear sizes share the same flow-control design and media layout – they scale up in flow rate and media volume as the numbers get bigger.

• Suitable for: freshwater community tanks, planted tanks, nano marine setups, and any 18-76 L aquarium wanting adjustable flow for bettas, shrimp or fry.
• Not suitable for: aquariums over 76 L, or tank rims/glass thicker than 2.4 cm at the mounting point.

• 1 x AquaClear AC20 filter housing and motor
• 1 x intake strainer with adjustable flow control
• 1 x media basket with foam insert, activated carbon insert and BioMax insert fitted

Rinse or replace the foam insert monthly. Replace the activated carbon roughly every three months, since spent carbon stops adsorbing and can start releasing what it's captured. Rinse the BioMax every two months in tank water (never tap water) and replace it roughly every three months – never replace all the BioMax at once, since it carries your biological filtration. Replacement media: foam insert (Fluval A598F), activated carbon insert (Fluval A597F), and BioMax for AC20/AC30 (Fluval item 19660).

Operates on Australian 230-240 V/50 Hz mains. As with any aquarium appliance, run it through a residual current device (safety switch) and keep the power cord looped below the socket to stop water tracking down the cord.

Fluval's standard warranty on AquaClear power filters is 3 years from purchase, extendable to 5 years total with online registration within 30 days – this is in addition to your rights under Australian Consumer Law. Standard parcel delivery Australia-wide.

Is the AquaClear 20 self-priming?

No. Fill the filter case with water before switching on, set the flow lever to its lowest setting for the first start, then allow 30-45 seconds for the siphon to establish.

Can I run the AC20 on a saltwater nano tank?

Yes. Fluval rates the AquaClear range for both freshwater and marine use up to 35°C.

Will the flow be too strong for a betta or fry tank?

The intake strainer has a built-in flow control lever, so you can wind the output back well below the rated 379 L/h without losing filtration – this is the main reason AquaClear is a common pick for betta and fry setups over fixed-flow filters.

What media does it come with, and can I add more?

It ships with one foam insert, one activated carbon insert and one BioMax insert in the media basket. You can swap the carbon for other chemical media, or add extra BioMax in place of carbon once the tank is established, as long as it fits the basket.

How often do I need to replace the media?

Rinse the foam monthly and replace it as it breaks down; replace carbon roughly every three months; rinse BioMax every two months and replace roughly every three months, staggered so you never remove all of it at once.