From looking at your filter on google, i would say there is probably something going round in the wheel, or up against the impellor. Is it the hang on back type?
The stuff it blew out when you started it back up was probably indeed crud from inside the filter housing, no big issue, my shrimp love it, but it will clear over time, normally a few hours max, perhaps a day, fdepending on the lph of your filter.
I would recommend taking out media and putting it in a bag of tank water while you strip the filter box down and find out whats in it.
Hope this helps.