Does anyone here have a red sea nano filter?It is for tanks that are 3 gallons..I picked it up at Petco today and it was on sale for 7 dollars.I put it all together and its kinda cute...its like a aquaclear..but tiny..

..the only problem is, I have an extra piece ..I dunno where it goes and it didn't come with a manual..It's a little tan circular piece( will get a picture in a little bit).Is it really just an extra piece?

I thought that maybe it snapped onto the adjustable piece, but it doesn't stay on there it kinda just ..falls off...

Is it just for "looks"....haha