I had a sump/refugium that served as both. I had a couple of inches of rock rubble in the bottom, with chaeto and dragons tongue floating above that. Smaller reef system, but it worked great! I only used a daylight spring type fluorescent bulb in a reflector mount & it grew macro pretty fast!
Fwiw,
I never ran ICP tests, just did the usual 40% water changes & dosed for cal+alk. Corals & fish were all happy but I didn’t grow sticks then either. Softies & LPS only. I did have a PFO programmable LED array for lighting above the tank though.