Hey guys so I'm sitting here watching tv and my fluval 406 starts making crackling noises like air got in the filter, a few seconds later it shuts off and dies. I messed with the impeller, the filter is spotless and clean, it makes constant crackling noises and sounds like the impeller is jumping around inside. I can't have a dead filter as no stores are currently open and my 55g full of peacocks which I'm currently treating with melafix will not be happy. Any advice?