The Aqua One Tropical Starter Kit 21L takes the Aqua One Sponge 54s (25054S) as its filter media; Australian sellers list it from A$4.44 each as of 7 November 2026. Fitment confirmed against the manufacturer's compatibility list.
Your aquarium filter
Aqua One Tropical Starter Kit 21L
Aquarium filter
Confirmed against Aqua One's listConfirmed against Aqua One's own compatibility list
Not yours? Change
Takes the 25054S filter media
Sponge 54s (25054S) · 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 25054S
Filter media · check the code on your old filter.
Other Aqua One aquarium filters that take the 25054S
GenuineGenuine Aqua One
$4.44 each
2-pack $8.88
Aquarium Spare Parts · 7 NovLowest genuine · Aquarium Spare Parts · checked 7 Nov
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 · $4.44 each · 2-pack $8.88
Aquarium Spare Parts. Every seller we track is listed below. Some links earn us a commission. Some seller links earn us a commission, at no extra cost to you.
This aquarium filter also takes a carbon filter
- Aqua One Carbon Cartridge 54c (25054C)Open Aquarium Spare Parts$5.44 each · 2-pack $10.88
Separate from the filter media. Reduces dissolved waste, odours and discolouration (activated carbon). Replace every 2 months.
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AUD, before delivery. Each price shows when it was checked.
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How long it lasts
Replace it when it clogs, breaks down or no longer holds its shape, Aqua One says; until then rinse it in a bucket of aquarium water each time you clean the filter.
How to change the filter media in your Aqua One Tropical Starter Kit 21L
Watch the guide or follow the steps.
- 1Unplug the filter at the power supply and lift it off the back of the aquarium.
- 2Remove the dust cover (lid), drain the water left in the filter body over a sink or bucket, and take out the carbon cartridge and the sponge.
- 3Rinse the sponge gently in a bucket of aquarium water, only to remove solid waste: Aqua One says never to rinse it with tap water. Shake the carbon cartridge in the same water to flush out waste.
- 4Put the sponge back between the carbon cartridge and the front of the filter, or a new one once the old one has worn out.
- 5Hang the filter back on the aquarium, fill the filter body with aquarium water until it overflows back into the tank, replace the dust cover and turn it on.
Every number this part goes by
- Retail name:
- 25054S
- Retail name:
- 54S
Sellers list any of these; they are the same part.
About your Aqua One Tropical Starter Kit 21L
Aqua One aquarium filter — Tropical Starter Kit. Its filter media is the Sponge 54s (25054S), part 25054S.
Also in this aquarium filter: Aqua One Carbon Cartridge 54c (25054C) (every 2 months).
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 4 Aqua One models
Common questions
- Which filter media fits the Aqua One Tropical Starter Kit 21L?
- The Aqua One Tropical Starter Kit 21L takes the Aqua One Sponge 54s (25054S).
- Where can I buy the 25054S in Australia?
- We track 1 Australian seller for the 25054S; the lowest listed price when we last checked was A$4.44 at Aquarium Spare Parts. Prices are re-checked daily and dated on this page.
- How do I fit the 25054S in an Aqua One Tropical Starter Kit 21L?
- 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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