Refugiums are not useless if they are done the right way. Having a small 3"x5" rectangle with chaeto in a 100 gallon tank is almost useless. having a 40 breeder where one half is full of chaeto and live rock, and the other half has a skimmer, and heaters is not useless.
I personaly dont put any divisions in my sumps because I think (personal opinion) that they just waste space. My Skimmers outtake is right above my return pump and i never had a micro bubble issue in any of my tanks. So, what i do is throw 2-3 big live rocks, and trap the chaeto in between. I like to form a U shape and trap it in a corner. The chaeto stays together and I have a pwoerhead that creates flow in the refugium/sump (on top of the flow created from the overflow and skimmer). The result is a refugium/sump that has no dirt or rotten food in corners, because it has plenty of unrestricted flow.
That is the way I do it, and I am not saying it is the best way, or that my way is the only right way. But it does 100% solve the issue of accumulated crap and 'how do I clean my sump?" issues.
