Cascade Internal Filter Q's

[Dragonmommy]

Hi all. I purchased a cascade internal filter, its the 600 model for a 55 gallon tank. I will be upgrading and/or adding additional filtration but this was the largest cascade my [acronym:86324389b2="Local Fish Store"]lfs[/acronym:86324389b2] had in stock.
I have two questions.

1. This thing is powerful and makes a current in my tank that rivals the current portrayed in Finding Nemo. Is this normal? Will it upset my fish (Lake malawi's and Goldfish, don't ask) I have it turned down as low as it goes, but its still so powerfull all my (fake) plants are crooked!

2. After I set up the tank and filter, and turned it on and had it successfully running my 4 year old picked up the packaging it came in and found another part. It looks like a wheel for a bicycle with spokes. Its blue plastic like the outer shell of the filter. Any ideas what this is and what i do with it?

Thanks so much!