The Aqua One Aquis 550 Series II takes the Aqua One Media Set 401p (25401P) for Aquis 550 Series II and Aquis 750 Series II as its filter media; Australian sellers list it from A$24.88 as of 29 October 2026. Fitment confirmed against the manufacturer's compatibility list.
Your aquarium filter
Aqua One Aquis 550 Series II
Aquarium filter
Confirmed against Aqua One's listConfirmed against Aqua One's own compatibility list
Not yours? Change
Takes the 25401P filter media
Media Set 401p (25401P) for Aquis 550 Series II and Aquis 750 Series II · check the code printed on your old filter before ordering.
Your aquarium filter
Aquarium filter
Confirmed against Aqua One's listConfirmed against Aqua One's own compatibility list
Takes the 25401P
Filter media · check the code on your old filter.
Other Aqua One aquarium filters that take the 25401P
GenuineGenuine Aqua One
$24.88
Aquarium Spare Parts · 29 OctLowest genuine · Aquarium Spare Parts · checked 29 Oct
CompatibleCompatible option
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No compatible seller tracked yetNo compatible seller tracked yet
Genuine: made by Aqua One. Compatible: another brand.Genuine is made by Aqua One. Compatible is made by another brand. Check the seller's page for the size and models it fits.
Lowest price · $24.88
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This aquarium filter also takes a fine pad
- Aqua One Wool 401w (25401W) for Aquis 550 Series II and Aquis 750 Series IIOpen Aquarium Spare Parts$5.44 each · 2-pack $10.88
Separate from the filter media. Reduces micro-particles (fine wool, mechanical).
Compare 1 seller
AUD, before delivery. Each price shows when it was checked.
Opens Aquarium Spare Parts in a new tab. Their page is the source of truth for price, delivery and returns.
How long it lasts
Replace it piece by piece: Aqua One says to replace the wool regularly and the sponges once they clog or lose their shape.
How to change the filter media in your Aqua One Aquis 550 Series II
Watch the guide or follow the steps.
- 1Turn the canister filter off at the power point and unplug it. Close the taps or flow valve and disconnect the tap connector from the head unit (Nautilus: lift the locking lever).
- 2Fill a bucket with water from your aquarium. Release the clips, lift off the head unit and take the media baskets out of the canister.
- 3Take out the sponges and the white wool. Dunk the baskets of biological media a few times in the bucket of aquarium water: Aqua One says this keeps the chlorine in tap water from killing the good bacteria on it.
- 4Rinse the sponges in the bucket of aquarium water and fit the new pads from the set where the old ones sat: Aqua One says to replace the wool regularly and the sponges once they clog.
- 5Put the media back in the same baskets and order, refit the baskets and head unit, then prime and restart the filter as its manual describes.
Every number this part goes by
- Retail name:
- 25401P
- Retail name:
- 401P
Sellers list any of these; they are the same part.
About your Aqua One Aquis 550 Series II
Aqua One aquarium filter — Aquis Series II canister filter. Its filter media is the Media Set 401p (25401P) for Aquis 550 Series II and Aquis 750 Series II, part 25401P.
Other media the maker lists for this filter: Aqua One Sponge 15ppi 401s (25401S) for Aquis 550 Series II and Aquis 750 Series II. Coarse 15ppi sponge sold on its own (also in the media set).
Also in this aquarium filter: Aqua One Wool 401w (25401W) for Aquis 550 Series II and Aquis 750 Series II.
Where the model number is: The model is on the filter's lid, motor head or a label on its side (Fluval 307, Eheim Classic 2215). For a tank with a built-in filter, use the tank's name.
Fits these 2 Aqua One models
Aqua One2 models
Common questions
- Which filter media fits the Aqua One Aquis 550 Series II?
- The Aqua One Aquis 550 Series II takes the Aqua One Media Set 401p (25401P) for Aquis 550 Series II and Aquis 750 Series II.
- Where can I buy the 25401P in Australia?
- We track 1 Australian seller for the 25401P; the lowest listed price when we last checked was A$24.88 at Aquarium Spare Parts. Prices are re-checked daily and dated on this page.
- How do I fit the 25401P in an Aqua One Aquis 550 Series II?
- No tools, a few minutes: 5 steps, listed on this page with the replacement video where the maker has one.
- What happens if I don't change it?
- Spent carbon stops removing odours and discolouration, and clogged pads slow the flow, so the filter moves less water through the tank.
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