consider this thread subscribed. I like the idea of cutting the concrete and puting the footings down to hold that much extra weight. I think now you shouldn't have any doubt it'll hold. It sounds like you have put a lot of planing into the tank and it's going to look great. Going smaller would have really would have ate at you in the future. You obviously weren't happy with the previous tank size, hence the new tank, so why would you cut yourself short. Is the frag tank going to stay in the middle of the floor because i love that idea. Being able to walk all the way around any tank is something I love. good luck on the build, and great job at making hundreds of people jealous.