I'm guessing from the dimensions this is a 20 long??
No reason why it can't be done. You don't really need to separate the inflow & skimmer sections. Just split the rear section in half.... left side for for the intake (recommend a filter sock) & skimmer, flow forward across the 'fug, and then back into the return. Personally, I'd put a small powerhead or two moving water around in the 'fug.
Wanna calculate the cost of that new reef tank?? Take your worst nightmare, double it, and you're halfway there.