With a little innovation you can totally do both!! I was able to get Miracle Mudd into my 29 g bio cube successfully with PS and refugium!!
What I did in the refuge on my 90 was the use of that plastic egg crate, see pic, cut some of that and build a wall around PS. Fill it with real small live rock, almost rubble. And pack it in there. Also, I love Miracle Mudd or you could make any kind of DSB. Just cut a 1 or 2 litter bottle like the Fiji water bottles (square) cut either the long way, or the top off, fill with any kind of dsb media, and just slide it in. It's is my invention, I've not seen done anywhere else, but right now my 3 week old 29g BC is doing great!! Corals and fish are thriving. Then place your chato or clourpa algae on top, get a light, and you're good!!
IMHO, there is always room for a fuge!!
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