These days many don't run a true refugium, or 'fuge', anymore
A refugium used to be a place where one would grow pods, macro algae, and usually would keep deep sand beds with LR
So, are you looking to run a sump with some equipment and some chaeto algae ?
Is this your goal ? If so, it's not really a 'fuge' per se, but a sump with chaeto
Thought I'd try to clarify the topic ...
What do you
really want out of a sump for your tank ?
Tell us what you'd like to have in it ....
Sorry if I missed the true meaning of your first question after reading through the thread