I have a 84Lx20Wx36H acrylic aquarium fully braced. All sides are 3/4 with top and bottom 1/2. I recently moved the tank witch it was purchased second hand. Now the tank is visible down the length of the aquarium and I can see bowing about 1/2in. Using a 4ft level across the front. It's very hard to find any information. I just want to know if the tank was manufactured correctly and is safe.