correct. a lot of fuges are full of chaeto and the skimmer, bioballs, etc are in the sump. if you are using the sump/fuge as a nitrate trap its going to be an algae zoo with equipment all sticking out which is why most people hide them. we are gonna have chaeto in our fuge but it will be contained.
for us the sump/fuge is all about increasing our total water volume to buffer rises in levels. most of what we will have in there will be scavengers so i dont expect much worry over increased bioload unless we add a bunch of fish.