When macroalgae goes asexual, it releases its gametes into the water column, and the excess nutrients are then passed into your system and you get algae all over the place, not to mention crappy water quality. Growth of macroalgae is good. Reproduction however, it not (at least by asexual means). Some people leave their refugium lighting on 24/7 in order to avoid this.
Chaetomorpha seems to be one of the best/most popular for refugiums at the moment. I don't know about baddies though, perhaps someone else can supply that info.
I haven't got a refugium but am hoping to set one up fairly soon. I seem to have all the parts for it but just need to find some space
Hope that helps a bit
Christy
