Some of them have a tool you can use to remove it but you can do it without. I have had them get stuck. Get it wet again, if that isn't enough try a little vegetable oil in it but make sure you wash it well later. Or call the company and ask them what they suggest?

Thanks Sherry, could you describe what the tool is, or looks like? I'm thinking I may try to run the pump in a 50-50 vinegar solution for a few hours - maybe that would loosen up whatever's inside it.

Where would you put the vegetable oil? there is no opening inside.

How did the vinegar work? I just realized your pump had the bigger shaft, and it looks like you can't get the oil past the impeller. I get parts from Webb's online and they carry the hy-drive pumps. I'd probably call them and ask.

Its been running really well in the 1/2 vinegar and now in plain water - Im impressed how quiet it is, which suggests that there's nothing in there interfering with the operation of it.... but still cannot get that rotor thing out. Beginning to wonder if it is supposed to come out.... in spite of what some directions say.

Butting into the conversation. I looked for directions, this is the skimmer pump? I hate to ask, but there should be 4 screws to remove first? Sorry, I absolutely just Googled for an answer.

Here's what I found, look at the 'more information' tab

http://www.drsfostersmith.com/product/prod_display.cfm?pcatid=23800

Thanks but.... yes I have the volute off. Its the cyclindrical metal rotor thingie (with fins on one end) that's supposed to just pop right out. Theres a you tube video that shows it just sliding right out when they pull on the fin end.

Did you ever get it out?

No - called someone at pondmaster and they said stick a butterknife in it to loosen - just ruined the knife is all. Oh well. I'm just going to redefine it as a non-problem, because other than being unable to take it apart, it seems to be working fine.