With skimmers you do get what you pay for. Having aid that, I have several small skimmers and I find I like the aquaticlife one the best. They are about $40 used on ebay and $60 new. Much better than the biocube skimmers and the new fluval skimmer.
If ypu can manage to keep up water changes you can skip the skimmer in such a small tank. I did in the past and just stuck with a larger hang on back filter. I only added a skimmer a few months later when I was going to upgrade the tank.
Hope that helps.
180g Reef - 60g Rimless Reef -90G FOWLR- 125g Malawi Cichlids- 40b REEF- 34g Fresh Planted-working on- 20L FOWLR- working on
I have a mix of many different saltwater fish amongst my tanks, but I love my Tangs most of all.