Ok, so for this installment of stupid questions from Trip

New project, after the loss of one of my pets, my frilled dragon, I found myself with an empty 55 gallon tank, figured I'd set it up again as a fishtank, as well as a pair of 10's on a stand near it (hamsters are long gone).

Wife has been wanting a saltwater tank, so my wheels start spinning and a thought comes to mind, birthday present

Ok, so long story short, I decided rather than two tanks, I wanted invertebrates, she wanted more aggressive fish, I'm setting up a 75 on top, with a 55 below for an invert/refugium tank, and process the whole thing as a natural environment.

The 75 is occupied by a 3' monitor, who needs a bigger house anyhow, that'll be another project (8-9' long, 3' wide enclosure in my office, zoo style)

55 gallon metal tank stands have room for one above and one below, but not enough height. We had a 55 on top and 40 below (original plan). They're kinda wobbly, too wobbly to go for the 75 gallon version, most of which are shipped as slip together rickety crap.

I need to design a dual level tank stand, steel, for a 4'x18" tank on top and a 4'x12" tank on the bottom, flush on the front. I need to figure out leg and base arrangement and sizing, with a possibility of upgrading to a 75 on bottom, 90 on top later.

For reference, we're looking at a potential of 1000lbs per shelf, tank, water, rock, etc. (maybe a bit more on top if we go 90). Lots of weight.

So, what dimension steel, I was thinking of welding a box of square tube for each shelf, then heavy angle for uprights, with bases and adjustable machinery feet to level. Bracing on the sides and back for added rigidity, corner gussets perhaps?

Thickness will determine process, but it needs to be dead sure solid, multi-pass TIG?

Thoughts appreciated.