The Aqua One Horizon Black 65 takes the Aqua One Media Set 81p (25081P) for Nautilus 600 and Nautilus 800 as its filter media; Australian sellers list it from A$25.88 as of 30 October 2026. This fit is not yet confirmed against the manufacturer's list.
Your aquarium filter
Aqua One Horizon Black 65
Aquarium filter
Not confirmed by Aqua One — check your old filterNot yet confirmed by Aqua One's own list — check the code on your old filter
Not yours? Change
Takes the 25081P filter media
Media Set 81p (25081P) for Nautilus 600 and Nautilus 800 · check the code printed on your old filter before ordering.
Aqua One's spare-parts finder lists the Nautilus 600 (94111) canister for this tank; that canister takes media set 25081P.
Your aquarium filter
Aquarium filter
Not confirmed by Aqua One — check your old filterNot yet confirmed by Aqua One's own list — check the code on your old filter
Takes the 25081P
Filter media · check the code on your old filter.
Aqua One's spare-parts finder lists the Nautilus 600 (94111) canister for this tank; that canister takes media set 25081P.
Other Aqua One aquarium filters that take the 25081P
GenuineGenuine Aqua One
$25.88
Aquarium Spare Parts · 30 OctLowest genuine · Aquarium Spare Parts · checked 30 Oct
CompatibleCompatible option
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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 · $25.88
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AUD, before delivery. Each price shows when it was checked.
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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 Horizon Black 65
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:
- 25081P
- Retail name:
- 81P
Sellers list any of these; they are the same part.
About your Aqua One Horizon Black 65
Aqua One aquarium filter — Horizon Black aquarium. Its filter media is the Media Set 81p (25081P) for Nautilus 600 and Nautilus 800, part 25081P.
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 5 Aqua One models
Horizon Black 130. Aqua One's spare-parts finder lists the Nautilus 800 (94112) canister for this tank; that canister takes media set 25081P.
Horizon Black 65. Aqua One's spare-parts finder lists the Nautilus 600 (94111) canister for this tank; that canister takes media set 25081P.
Common questions
- Which filter media fits the Aqua One Horizon Black 65?
- The Aqua One Horizon Black 65 takes the Aqua One Media Set 81p (25081P) for Nautilus 600 and Nautilus 800. Aqua One's spare-parts finder lists the Nautilus 600 (94111) canister for this tank; that canister takes media set 25081P.
- Where can I buy the 25081P in Australia?
- We track 1 Australian seller for the 25081P; the lowest listed price when we last checked was A$25.88 at Aquarium Spare Parts. Prices are re-checked daily and dated on this page.
- How do I fit the 25081P in an Aqua One Horizon Black 65?
- 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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