Get the C-360. You'll likely need it on a 55g anyway. Print out this page http://www.kensfish.com/marinelandcanisterfilters.html from "kensfish.com", its on sale for $127 (at the bottom of the page). Just have Petsmart pricematch it and there you go. No shipping charges and best of all you get it right away. :thumb:
Khris
Khris