Looks like a very young setup. Unless you cleaned out everything perfectly. You got a light over the DSB with no sign of any growth on the eggcrate above the sand.
Anyway, measure that first section of the sump with the big crushed corals, I'm sure a TS1 skimmer or similar will fit in there if you remove the first glass section.
Had you done a power out test? I see the return is rather low and you do run your sump rather deep. Is there enough space left in the sump to handle the extra water returned?