I have a 20 gallon tank I used as a quarantine tank. It has set for 6 months with no livestock in it. I was wondering if there was anyway to turn it into a refugium. I have read about the algae and all but should the tank flow into the sump then pump into the refugium or vice-versa. I have a155 gal with built in overflows that go to a wet/dry filter now. There are just a few bio-balls in there now too quiet the water fall now. I would like to keep the 20 0n its display stand and set it next to the big tank. Is this possible? any suggestions would be greatly appreciated. Thanks Andy.