skilters dont work. Pretty much all of the "all-in-one" things never work, or they never work very good. Just the company trying to make a product look very usefull and versitile so that newbies (and others for that matter) thing its really good. But i have heard that skilters are somwhat noisy too.
And like mrmexreefer said...dont bother w/the nano fission skimmers...they dont work either.
IMO, a 5.5 gallon tank does not need a skimmer. Sure, it could help...but imo, not worth it. Theres nothing that size that i would consider paying the money for to skim that, when weekly water changes are gonna be fine for it.