The 10 gal
has fish right? You don't want to remove the 10 gal
's filter all together if there are fish in there. Also running the 55's filter on the 10 will only seed it as far as the stock you have in the 10, so it wouldn't be able to hold a 55 gal
full of fish. You could grab some substrate from the 10 and put it in a mesh bag and put it in the 55's filter or right under the intake. You could also grab a small portion of the filter media from the 10 and add it to the 55; just watch the 10 gal
for a mini cycle. Since that cycle just completed you don't want to mess with it too much.
Edited: you might want to consider buying a seeded (active) sponge filter from Angels Plus for the 55; that would probably help the most. http://www.angelsplus.com/FiltersSponge.htm