on high rise buildings, concrete is tested at 5000 lbs psi in break tests. set it up and watch your fish and have fun. the worst thing that can happen is your tank leaking.
So if my tank is 6x3 it'll be 2600 square inches and if a gallon is 8.5lbs then it'll weigh 2300lbs not including tank, stand or sump. It still sounds scary.
