I've got my 180 on order and I am ready to frame a stand. It's going to be set through a wall in my basement. I am cutting out an existing dividing wall and framing the stand behind. The floor isn't exactly level, there appears to be a hump right where the middle of the stand will rest. I can tell the floor has moved in the 50 years since its been poured because there is a crack running through that spot. Should I grind that spot down a bit and shim the rest of the stand level? Or should I pour some self leveling compound in a form in that spot? I'm concerned that over a long period of time that spot could still shift causing uneven pressure on the tank. Am I really over thinking this?