I have a 100 gallon display reef with a 80 gallon sump. Within the sump there's a refugium that holds about 30 gallons of water. I put kent marine bio sediment (about 4" deep) in the refugium with a decent amount of live rock. The lighting on the refugium is counter cyclical to the display tank (turns on at night). I also have chetomorpha in the refugium.
I have a couple of questions on the refugium - can I move the live rock from the refugium to the other parts of the sump (where there's no lighting)? or does the live rock require lighting certain amount of the day? How much live rock can I put in a sump? Is there such a thing as too much live rock for a system? Obviously you lose water volume through displacement, so that's a negative to too much LR