I would reccommend that you leave it on the floor or just make a giant concrete stand covered in wood. I absolutly would NOT reccommend only 1 inch of plexiglass. ATLEAST 2-5 inches! It can EASILY spark a leak or just completely break open.

I don't think any of the answers here will have much experience with tanks that size, I certainly dont.

The height of the tank is the main issue when working out the glass or plastic thickness.

At 4ft tall, do you even need a stand?. Put it on a stand and the tank will be 6-7ft off the floor. Need a ladder to even feed the fish.

Probably need to check the foundations of the house as well, as you say, it will weigh close to 2 tons with the tank and gravel.

For info on a tank like that - try this forum.
http://www.mons…

Ian

I don't see why you couldn't build it, its definitely possible. You can technically "build" any size aquarium, however depending what you want the tank for, saltwater reef, freshwater planted, etc, really anything that is going to require high power lighting, the depth may become a issue. The 72' length is common, however the 4 foot depth is not lol. That's a deep tank. You may consider increasing the length and width and shortening the depth, this may require multiple lighting fixtures, however your corals or plants would do much better. If your going for fish only or fowlr or just a big freshwater or a big fish species tank, then I don't see any problems with the tank. As far as the stand lol goodness. Yes it will definitely weight at least 3500 lbs. Big issue here is the stand will need to be kept on concrete irregardless if you have a stand or not. Your typical house floor will most likely not hold that much weight for an extended period of time You could build a stand and my father has constructed stands for much larger tanks. (He's in his 60's and has kept aquariums since I can remember. He always dabbled in woodwork, but started building his own stands about 10 years ago. He's built all of the ones I currently use. I haven't really had the time to set and watch him, however I do know he reinforces the tank with 2x4 braces all along the inside and uses a central 2x4 brace as well. This gives a little less storage room in the interior, however better to be on the safe side I suppose.) If you have someone who does woodwork in your area, and Im sure you do, you can give them the dimensions and what you want, tell them how much you need the stand to support, the material you want it constructed out of, and they will build it for you. The price is usually almost exactly what a stand purchased for those exact dimensions will cost unless you use expensive or rare wood.

Truly best of luck