I am setting up a 75 gallon tank with a 40 gallon sump. The tank is not reef ready and will use a HOB overflow. The sump will be a modifies acrylic tank that measures 48 long X 13 wide X 16 high. I would appreciate suggestions on how best to compartmentalize this tank. Also, what would be the best skimmer? In sump skimmer or external? Live rock vs DSB, or both? I am attaching pictures of the tank I want to use for the sump. By biggest issues with modifying the sump are the divider in the tank and the 3 to 6 inch lip around the top. Thanks in advance for the input.