Should 1.5in thick acrylic all around be sufficient for a 12’Lx3’Dx4’H tank? Should I do steel or aluminum stand & how thick?

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looking to build a minimal reef tank with schools of my dream fish so save the too tall comments lol

 

[lapin]

I don’t think you will find an answer on this forum. Your question has some variables. Bracing, top, etc.
My suggestion is you get a quote from a professional company that builds large tanks. That should come with the thickness required. You should also let them know you do not want any visible bowing.
Good luck with that big tank.