Filters wont work after cleaning?

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Aquarium Advice Newbie
Sep 14, 2009
Help. Im new to fish keeping and to this forum.

I was given a tank and equipment which was in a bad state. I cleaned up the filters and changed the media in them but now both filters wont work. One is an Interpret PF3 and the other is a smaller filter made by Rena. What could be wrong? The previous owner of the filters has confirmed that we've put them back together correctly.

Also should the spouts where the clean water is ejected from the filter be slightly above water level as we've been getting conflicting advice about this?

Any advice most appreciated.


No, i just stuck them back on the glass and switched them on. The previous owners did exactly the same. How do i prime them?
Both filters have been left submerged in tank overnight and then switched on in morning but still not working. Is this sufficient to fill them with water?
No you will need to take a pitcher of H20 place it into the filter box , then plug it in .. If that doesnt work pull the intake tube out and see if you have movement of the impeller , if you dont you can try to remove the impeller (after unplugging) plug it in and drop the impeller to see if you can reseat it , if none of that works new filters would likely be needed .. :D
My Bad, I didn't realize they were in tank filters. Did you take it apart and clean the impeller? Also, is the impeller able to spin freely by hand (It may be jammed).
Neither of the impellers move freely by hand. The smaller Rena pump - impeller slightly stiff but turns 360. The Interpret PF3 - impeller really stiff only slight range of movement. How can i fix this?
The impeller is a magnet, and is a bit "stuck" to the motor magnet so might not turn freely. Simplest way to see if it is running is to submerge the filter (disassemble enough so the impeller is visible) and plug it in briefly to see if the impeller turns. <This will make quite a splash - so do it in the tub or something.>

If the impeller is not turning, you will need to pull it & clean it. There is usually a little cover/retaining ring over the impeller. Once you remove that <the blades of the impeller will then be completely free>, you can pull straight up & out. The magnet will exert a bit of force so you will need to pull, but you should not have to force anything.

Check that there is no sand or other deposits in the impeller housing/ magnet. With hard water, there is often a film of hard water scale. You'll need to soak that off with vinegar (or CLR lime remover if it is really bad.) Clean & reassemble. It is recommended that you clean the impeller monthly in areas with hard water to prevent it seizing.

With the impeller out, check that it is not broken. <The magnet should engage the blades with 1/4 turn.> You'll need a new one if it is. <Happened to me this WE with my pump! :( >
as far as your other question...

what conflicts have you been getting? you want to have some motion on the surface of the water. The only submersible filter I had had a spray bar. I left it just below the surface and it caused a good amount of surface movement.

what reason would someone give to have the output totally under the surface?
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