Help! Unable to prime Aqua One Aquis II 750


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Sep 17, 2021
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Birmingham, UK
Can anyone offer any advice, please?... I've got an issue with my Aqua One Aquis II 750 external filter. I am currently treating my tank, so I opened the filter to remove the carbon sponge. When I put it all back together and restarted it, I was unable to prime the pump.

The priming button has always been very stiff and difficult to press (is this common to all Aqua One Aquis filters??), but it has now stuck down in the fully depressed position. I can't get any movement on it whatsoever.

When I plug it in I can hear the impeller spinning, but there's no throughput. All the valves are open, the canister is full and the suction pipe siphon is primed. As far as I can tell, it's all working fine and it just needs a few presses of the priming button, but I can't shift it. Has anyone come across this and solved it, or is it new filter time?


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