Hmm.. I can't say what we should do about the term "refugia" (or even that we should), but I can tell you, Mr. Tran, that the grammar police (much to my surprise) will actually allow you to apply the word "who" even to entirely inanimate objects! 8O (Imagine my surprise)
However, that being said, if using the word "which", it must usually be preceded by a comma "," except in the event of beginning a sentence or question. :mrgreen:
In my own opinion, I prefer "refugium" to be a more all-encompassing word, as "algae scrubber", to me at least, means a series of trays in which macroalgae are/is grown (see Antoine's feelings on mixing of macros, plus, he doesn't really like Caulerpa species, whereas I've had fabulous luck with them, but we've had that discussion already) alone - key word here being "solely" - sans sand, live rock, or other features that would lend a "refugia" feel to the set up (holdfasts and other means by which said algae may afix itself to any substrata notwithstanding).TM
(Whew! Talk about a run-on sentence! Oh! Mrs. Dupres, she must be rolling over in her grave!)
Also, a refugium may or may not require a great deal of supplemental lighting (especially if a total lack of macroalgae is um.. present), whereas by its very nature an algal scrubber would have a very real need for specific lighting.
