Fluval 404 help

So, I've got a fluval 404 that's been working fine until last night. I got it with my tank. I changed some of the filter media and put it back together and plugged it in.

It came on, ran for a minute, rattled loudly and quit. So I took it apart and checked the impeller shaft, found that one of the clips on the impeller cover is broken. the other is fine, and it seems to still be held in place.

Further investigation reveals that the little black plastic piece on the end of the impeller shaft (It fits inside a bushing or something in there to keep the impeller centered) had come off and was loose in there. I put it back in place, put it back together, and turn it on. Works fine. Thinking my troubles are over, I go to bed.

This morning I walked in to hear it rattling loudly and not pushing any water. I turned it off and went to school.

I get home and take it apart and run water through the area the impeller fits into and clean it as best I Can with a toothbrush.

Turn it back on, and its been almost 2 hours, and it's rattling occasionally, when it rattles it stops pushing water. It only rattles for a few seconds, however, and then goes back to quietly pushing water.

I'm really confused, could this be caused by the broken clip in the impeller cover?? It really seems to be held in place fine. I'm about ready to then

 

Mine has been running with the same broken clip like yours for well over a year as best as I can remember,no problem.It sounds like your losing siphon for some reason,the impeller is rattling because its running dry.

 

If its not a problem with losing siphon,and your supply hose (into filter) is fine, it could also be a problem if you have too much media in your baskets restricting the flow.

 

I definitely don't have too much media in it.. And how would I be losing siphon... The hose is fine. It doesn't leak...

 

It could just be some trapped air that has gathered in the impeller chamber.Pumping the priming mechanism might help clear it.

 

Pick the canister up and rotate it around in all directions while its running to release trapped air.