I also have a coralife 65 that was for my 55. Works great but the pump and bubble difuser take a bit of room in the tank and don't look all that attractive. I have since moved it to my 72 for now while the 55 is using a freebie prizm. I plan on getting a aquac remora for the 72 in the next couple of weeks. Then the CL 55 goes back onto the 55. The prizm goes back on a shelf for emergency use. I think the prism is junk but it does collect the foam and crap that it should. But just not as well as my CL 65.
Why the change? The aquac remora has great reviews and can work with an add on surface skimmer. I have that bad slick on the surface and everything I tried so far doesn't get it. I am hoping I am not making a big mistake.
How much does it pick up? Depends on my water quality. If I dump some fresh shrimp in the tank for feed it foams up right away and collects a lot of fluid - clear but stinky. If I just feed normal and do my water changes I get more green gook as the week goes on. If I don't clean the cup daily I get about 1 inch or so of gook per week. If I don't do a water change that week (go two weeks) I collect more.
DO a search on skimmers and you will see a huge amount of opinions on skimmers.