I did the same thing Mr Cob did when I upgraded from a smaller tank. I have a sump with macro but I just couldn't let go of my CPR HOB refugium so that's still hanging on the big tank.
I justify it by saying the pods from the sump could get damaged by the pumps on the way up, the HOB refugium is much gentler on the pods. ;)

Clearly if somebody doesn't have one like that, they need one - buy Euclid's!