Skimmer size

[Palmer]

I'm looking at setting up a 60 Gallon cube system with a 20 G sump. I wanted to use a Tunze skimmer but I wasnt sure whether I should get the nano 9002 or the Doc 9005. I think the nano is specified for 55 G and the 9005 is for 55-528 G. Since I will have live rock in the tank (approx. 60 lbs) and the sump will not be completely full I wasn't sure if the Nano would be okay?

thoughts?

thanks!

Palmer