The refugium section of the sump on my 90g is 27"x12"x15" (21gals) with a 4" sandbed. I grow chaeto in it with a small amount of caulerpa.
(The caulerpa is there simply because it is too much work to separate it from the chaeto). Every couple of months I rip a good size chunk of chaeto out for nutrient export. I realized I hadn't done this for awhile so I checked it out. The sump is outside and gets a certain amount of natural sunlight so the macroalgae grows quite fast. Holy Crap! The algae was so thick and dense it had turned into a solid brick, filling the entire refugium. It was so thick I could lift it out as one solid piece. It looked just like a piece of lawn sod except that it was 12" thick. I chopped half of it away and threw it into the garden. Afterwards I realized I should have taken some pics first, Damn it! Maybe I'll grow it again and take some pics to post up.
