reguardless of what size i use for the DT im gonna use a 55g for the sump. i have some sort of an idea what to do as far as having a refugium in the sump. im just kinda curious of what other sumps look like.
Make the fuge as large as you can while maintaining enough room for the skimmer in it's compartment and a reasonable water volume in the return area. Personally mine has just enough space for the skimmer in it's compartment and evenly split space between my fuge and return area.