I would keep looking. You want a skimmer that is rated for double your water volume usually.
Are you having any particular issues with your tank that makes you want a skimmer? With a 30g tank you should be doing fine if you do your weekly water changes.
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.