Skimmer pump locked up?

I have a Bubble Magus BM-100 skimmer. It has been off my tank for around a month. I took it apart to clean it over the weekend and when I put it back together and turned it on, nothing happened. The pump hums and vibrates, but the impeller won't turn. Any ideas?

Thanks.

 

A piece of dried junk or a small grain of sand or even some hardened calcium can stop an impeller. Try turning it by hand to see if it's just a small thing.

 

Hindsight is 20/20 as they say... Always rinse equipment off before storing it.
Now for your pump, try soaking it in vinegar if you can not simply remove the impeller as Malcolm suggested.

 

If its not locked up it may just need a little help getting started again. My BM has the attman 2500 and I sometimes have to blow into the airline to get the pump running again after I disassemble it for cleaning.

 

Try a vinegar soak or mild HCL and water solution.

 

Thanks guys.