Current makes a skimmer called the Fission Nano for about 24 bucks, people on this board will tell you it worthless, I've personally run mine about three days once a month to remove the slick that forms on the the top from feeding and it does a great job.
I do a 10% change weekly and really don't think I need a skimmer on my 24g aquapod for anything other than cleaning the slick. if I took the time to strain my frozen cubes through cheesecloth to remove the oils i probably wouldn't need it at all, but I think straining might be removing beneficial nutrients.