I'm planning to build my steal stand for my up coming dream fish tank with industrial shelving beams like you see at Costco or Home Depot.
The 8 foot beams are rated for 7160 pounds each. The way my friend is going to weld the stand, it will be able to handle just about any weight I want.
I believe in over building the stand, just for my piece of mind.
As for my tank size it's going to be between 400 to 500 gallons, which I'll probably go with acrylic, since I live in the center of earth quake country in San Mateo County, Ca and I need the tank to hold up with extreme stress levels, which glass is more prone to fail.
Randy