Setting up my 28g JBJ NanoCube and wanted to bounce my filter/sump setup off you guys to ensure I am on the right track.

The back portion of the tank has 5 compartments (I think called a mini sump). Here is what I currenly have in those 5 compartments. Please set me straight if I am not using these compartments in the best way.

Outermost compartments (1 and 5) have return pumps, I have a UV sterilizer attached to one of the return pumps.
Compartment 2 has the Oceanic protein skimmer.
Compartment 3 (middle) has the filter media basket, of which I have removed the bioballs, but kept the filter and carbon.
Compartment 4 has the Jager heater.

Any advice is greatly appreciated.