I have a 300 gallon DT, and two 100 gallon Rubbermaid troughs. One is filled with three different macro algae. The other with skimmer etc... I bought the troughs at a local nursery.
I keep a dedicated 150 gallon refugium tank on my system. Most of my other sump tank space is empty at the time so it acts as an unlit refugium tank and I might add some dry rock to those sump tanks to create a better place for pods to thrive in the future.