Plywood aquarium wall bracing

[Night Ranger]

In about 4 weeks I will be bracing the walls of my 578 gallon aquarium and I won't have room for 2x4s on the back wall of
the tank so I decided to use 1-1/2"x1-1/2" square tubing with a wall thickness of 1/4". I have 2 options and that is mounting
7 vertical tubes on the back wall and two vertical tubes on each side or 3 or 4 horizontal tubes on the back and sides.
The plywood is laminated and is two inches thick so I have plenty of room to screw the tubes the the walls. The tank is
96x48x37.5. I will probably use 2x4s around the perimeter of the inside top with 5 cross braces and 1 of those on each end.
I will use a router around the inside edges of the 2x4s for plastic lids. Any ideas or votes for the location of the
steel tube bracing on the walls. I'm leaning towards a horizontal mounting of 3 or 4 tubes on the walls.

 

[Trouser Bark]

Any chance you might be able to get deflection calcs for the steel? It sounds like it's hell for stout. Why do you need to brace the tank at all?

If you're looking for maximum strength I'd consider installing it as a band around the tank rather than screwing it to the plywood. Maybe two bands (a high and a low) w/ vertical members connecting between on the rear and sides of the tank. It's a little difficult to envision why you would want that though. Is there a specific concern or is this a new tank you're just now building ?

 

[Night Ranger]

Any chance you might be able to get deflection calcs for the steel? It sounds like it's hell for stout. Why do you need to brace the tank at all?

If you're looking for maximum strength I'd consider installing it as a band around the tank rather than screwing it to the plywood. Maybe two bands (a high and a low) w/ vertical members connecting between on the rear and sides of the tank. It's a little difficult to envision why you would want that though. Is there a specific concern or is this a new tank you're just now building ?

It seems like everyone that builds a plywood aquarium uses 2x4s along the sides and back usually mounted in a vertical fashion.
From what I make of it its to keep the plywood from deflecting which could cause problems with Pond Shield cracking. I'm not using that product but I'm using aquarium safe epoxy from Amazon to seal under and over 6oz fiberglass cloth then I sand the top coat then I lay more epoxy then 4oz cloth and 2 more coats of epoxy over the 4oz glass. This gives me a very uniform thickness of 1/16" and good protection. I don't believe 1/16" thickness with fiberglass reinforcement is going to crack very easy unlike Pond Shield that is layered on real thick with heavy runs and no fiberglass except on their seems. All my work is being done on some carefully leveled saw horses with runners and cross members so the plywood doesn't warp when I'm working on it. The reason I went with 2" thick laminated plywood is I thought there wouldn't be a need for vertical or horizontal exterior reinforcement and there is a lot of surface area along all the edges for epoxy adhesive and to double up the screws. If you believe I could get away without reinforcement it would save me several hundred dollars and a lot of extra work but it's not about money it's about peace of mind.
This is my first build and one thing I don't want is to wake up with a soaking wet living room floor and and 10 very large fish
that I would have to scramble for a backup home. I could wait until I fill it with water and watch for deflection then if necessary I could drain it then brace the aquarium if needed. What do you think?