Fluval Flex Circulation Pump

• Genuine Fluval replacement – the WP500 (A14673) or WP1500 (A14677), the same pump fitted from new.
• Two variants, one listing – choose by which aquarium you own, not by guessing a generic pump size.
• Direct fit – drops into the existing filter chamber, no plumbing or rewiring.
• Restores flow and filtration – the pump drives water through the foam, carbon and BioMax stages as well as circulating the tank.

Fluval does not publish a wattage or voltage figure for either pump on its own spec sheets or in the Flex instruction manual – only the rated flow above is published. We haven't guessed a number here; if you need the exact power draw, Fluval's support line can usually confirm it against your unit's model plate.

230 L/h and 500 L/h are Fluval's rated figures measured at zero head, the same basis Fluval publishes for both pumps. Like any internal pump pushing water through a media stack and an output nozzle, real-world flow in the tank will sit below the rated figure once the foam, carbon and BioMax are loaded – Fluval does not publish a head curve for either compact unit, so we're not putting one on this page. If your tank feels sluggish with a new pump fitted, check the media isn't clogged before assuming the pump is underperforming.

1 x circulation pump, matched to the variant selected.

• Filter media. Foam, carbon and BioMax are sold separately and wear out on their own schedule.

Suitable for replacing a worn, slow or noisy pump in a Flex 34L/57L, EVO 52L or Spec 60L. Not suitable for the Flex 123L system, which runs a different pump entirely, and not a like-for-like fit for older Spec I–IV or EVO XII kits that predate this pump generation – check your model plate if unsure.

Most flow loss is debris on the impeller rather than a failed motor. At each filter service, lift the impeller out and rinse it and the pump housing in tank water; a scratchy or grinding noise usually means grit has worked in around the shaft, at which point the impeller (sold separately) is worth replacing alongside the pump.

• Fluval Flex impeller – the wear part inside this pump; worth fitting together if the pump has been noisy for a while
• Fluval Flex foam insert – replace alongside the pump if flow has been weak for a long period
• Fluval Spec/Flex/EVO BioMax – biological media that sits directly behind the pump

Supplied as a genuine Fluval replacement part. Your rights under the Australian Consumer Law apply in full and nothing here limits them. No separate manufacturer warranty term is quoted on this service part. Ships as a standard small parcel anywhere in Australia.

How do I know if I need the WP500 or the WP1500?

By aquarium, not by guessing: the WP500 fits the Flex 34 litre only. The WP1500 fits the Flex 57 litre, the EVO 52 litre and the Spec 60 litre.

Does this pump fit the Flex 123L?

No. The 123 litre Flex uses a different, larger filtration system with its own pump.

What flow rate should I expect once it's fitted?

Fluval's rated figures are 230 L/h for the WP500 and 500 L/h for the WP1500, both measured at zero head. Expect somewhat less once water is pushing through loaded filter media.

My pump has gone quiet rather than noisy – is it the pump or the impeller?

Check the impeller first. A cracked or jammed impeller often just stops turning rather than making noise, and it's the cheaper part to replace.