Just getting it out there that within a few weeks I will be selling my 30x30x30 cube. construction is all glass. Back is drilled for a closed loop with two 1'' returns, a 1 1/2'' for the closed loop return and another 1 1/2'' for the sump return. No overflow box currently, I just had an upswept 90. Tank doesn't fit through basement door, so I have to move it out the daylight basement window. This takes two people, three of four is better.