Hmmm, it defintely *could* be something in the impeller. Right before this happened there was a ton of crap I vaccumed out and a lot of it ended up in the catch basket, so it's always possible something slipped through into the pump itself. But when you say "removal of the front cover" what do you mean by that? I thought the pump/basket/impeller were all of one piece.

I'll go out and take a look today (and see if there are any internet videos showing me what you are talking about). The good news is the last pump they put in was done with screw settings on both of the intake and output pipes, so changing the pump isn't going to require any cutting (at least in terms of taking it out -- I may have to cut to fashion some fittings on the new one to fit this setup).