If it was me, I'd lose the bio balls and use that space for
LR and
LS. You will have to light it if you're gonna have the macro algae. I'd light it when the main tank lights were off or "reverse light" it. I have had a bad experience with bio balls in a
SW tank. Is the tank going to have
LR in it? Also, I wonder how the macro algae will do in the main sump? There will be lots of water flow in there...be something to look into. Also, if you're gonna have
LS in the sump, I think you'll need a dam of some sort in front of the pump intake to keep the sand from being sucked up. Sand is hard on impellers...learned that the hard way

Logan J