Sump questions

[hunggi74]

I bought a used Ecosystem sump for a great price but now I have to make it work. I'm setting up a 57gallon tank and the sump I want to use for a deep sand bed and a protein skimmer. The problem is that the first chamber is only big enough for a filter sock and the last chamber is only going to fit my return pump. The middle chamber is 16"x10". I'd like to have a deep sand bed in there along with some chaeto and use a hangon skimmer in there as well. I like the idea of a dsb but can't do it in the display tank because it has vents in the built in overflow three inches from the bottom. Or should I abandon the dsb idea and just have a big in sump skimmer in the middle chamber? Thanks!