Yeah, you are lightly stocked so the one skimmer will most likely be just fine. The skimmer will skim out excess organic matter and with only a small handful of fish two would be overkill. At least in my opinion/experience.
As you add more stock and/or acquire more corals you may see the one skimmer start to get overloaded and filling the cup really quickly, at that point I would consider a larger skimmer or running the two you have.
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.