Marineland c220 Filter

So I just got a Marineland C220 canister filter and it started up great works fine no leaks so far but there's a faint rattling my love noticed this morning (set it up last night) IT kind of sounds like the impeller so I took it down checked it over emptied it out adjusted all the media baskets, checked the impeller to make sure it was seated correctly and everything seems right.

Put it back plugged it in and still a faint rattle I shook it a little to free it of some of those pesky air bubbles as others have recommended but still I can hear it. It's far quieter then the splashing of my old powerfilter but I worry I'm going to burn something out? I know that with every powerfilter I used it needed a break in period so some slime would build up and effectively grease everything up so that it would all stabilize is this just what needs to happen or is there more to this?