Zeo-Carb. Half Zeolite, half Carbon filter media yes? That's going to be a PITA if you ever need to treat the tank with meds. The Zeolite will be removing all the Ammonia from the system (can be simplifyed to "fish waste" if you are un-formiliar with the nitrogen cycle and biological filters) and will also remove fish meds from the water. If the fish get ill, you have to remove it. What removes the Ammonia without it? Nothing, as there is no bacterial colony in the filter, as the Zeolite starved it by out-competing it. The result, Ammonia builds up and poisons the fish at a time when they are already stressed
Not a great media choice, and has no easy fix
You are also tied in to buying regular Zeolite replacements also, to keep the tank going
As Truck says, the skimmer is not needed in Freshwater. It cannot work in Freshwater, as the water isn't dence enough to create sufficiently fine bubbles. The lack of salt also stops any charges building up sticking dirt to the bubbles for removal, so it is effectively useless even when working correctly in FW
All the best
Rabbut