Help With Protein Skimmer Impeller Assembly

So this thing has been making a ruckus (HOB-1) Aquamaxx. Anyways took the impeller out and this little tiny plastic o ring came out (Pictured to the right of the assembly) Anyone have any clue where this goes??? I'm completely lost. The pump has been whisper silently and now is just really loud and obnoxious. It still spins and works as it is suppose to but it is way noisy. So where does this little plastic ring go?

The pump is the standard one that comes with aquamaxx HOB-1 Skimmers. I believe it is some sort of sicce but the pump says shark 1.0

 

I would look for any ware marks to see if something has changed, I bet o-ring just sat some where to keep the impeller in just the right spot and balanced right. I'd see how much it was to just replace it, I think they just get a little "loose" and it's nice to have a new one in there for the 8$ it cost me at the lfs, but I think they gave me a little discount.

 

Thread moved to the proper forum. The ASAP forum is for emergencies only

 

Contact Marine Depot customer service. No one knows that skimmer better.