GiulianoM;668059 wrote: Right, I forgot about that...
Are there truely 2 x .75" vertical supports on the inside?
There are three layers of ply along the top of the stand (face panel + 2 layers of ply reinforcing), and two layers at the verticals (face panel + 1 layer of reinforcing).
I think you should account for 3 layers everywhere, to give yourself some wiggle room in the available footprint area. You'll need the extra space for pump removal, skimmer removal, etc when cleaning/tinkering.
Dustin