refugium vs. sump

[insane_reef_keeper]

OK so after I finish the 60 cube build, I want to do a refugium as well with the wet/dry sump. I know I could do the whole gravity feed from the refugium to the sump and vice versa. Now my question is this, should I drill a ten gallon tank and connect the two together with bulk heads or run two separate units?

I do want to run a Kalk reactor and a Phos reactor, so having the room will be a bit of a issue. The inside area of the stand will be 24"x24"x 32" tall.