people with lots of fun money buy 3300gallon tanks. it is going in a residential basement with reinforced concrete slab floors. Still not sure what it will be made out of? Either FRP with acrylic windows, or steel with acrylic windows, or fiberglass with acrylic windows, or an all acrylic tank, if its built with just acrylic it will have 3"-4" thick pannels. same customer says he might want an even larger tank in his business. A gym.