Internal filter gives off strange noises...

[ClownLurch]

My internal filter gives off strange noises every time it’s switched back on after being turned off for planting, reshaping etc etc. It sounds like a cross between a giants stomache rumbling and rushing water once it gets going but initially like grinding gears on a missed gear change in a manual car.
I panicked first few times and switched off took it from the tank opened it and cleaned everything out thinking there was an excess of sand or plants in but there’s nothing in there and once it was restarted was running perfectly.
Its doing it again now after 70% water change. I’m leaving it while having a coffee to see if it’ll right itself but it’s not looking promising.
Is this normal? Is it just trapped air? Or something else?

I don’t fancy this carry on every time it’s turned off. Is there an internal box filter that doesn’t do this that anyone could recommend for a 120L/ 31G tank?

 

[seangee]

Every couple of water changes pull the impeller out and give it, the shaft and surrounds a good clean. I use a clean (unused) electric toothbrush head for this. May require minor disassembly to get to the motor. Even those that claim to be self cleaning aren't.

 

[Essjay]

Be careful! Don't loose the little rubber grommets that sit on the ends of the impeller shaft.

And if, like my filters, the impeller shaft is ceramic rather than metal, be careful you don't break it. (I always have a spare one in the cupboard just in case)

 

[ClownLurch]

There’s a loose bit I’ve just noticed in the bottom of tank below filter. 25 mm long Black plastic like a little axel with a wheel on one end. It’s working at the moment without this piece.
I may have a dismantle tomorrow.
Anyone got an idea what it is?

 

[Essjay]

Any chance of a photo?

 

[ClownLurch]

Any chance of a photo?

I wouldn’t hold your breath! I’ve been on the Internet and various forums for 20 years and still not learnt how to post photos or links to elsewhere!
I realise being Responsible for little fish lives means I’m gonna have to up my game in these matters. I’ll have a go tomorrow.

 

[Essjay]

I know how to attach photos with a pc.

If you have the photo stored on a pc, click 'attach files' under the reply box then search for the photo wherever it's stored and click open. Then just decide if you want a full photo or a thumbnail and click post.