Yea, I think since adding my tanks, my floors seem to creek more. I think I even feel more imperfections in the floor other places in the house because of it.....
If you hear your stand creaking I would thoroughly inspect it. Of course it could be like older houses in the summer that pop and crack in the night as they cool down and every thing contracts a little but I doubt that too lol
Well this can go one of two ways. House builders expect creaking sounds on a new house the first year or two as everything settles in. If the tank's stand is new and built having the screws hold the weight it could be advised as being "ok" but I would investigate it thoroughly. Creaking sounds may imply something is going to give. There is a big difference here though, houses have a small distance where it "gives" due to natures forces such as winds and soil erosion that cause the creaking sounds. Generally tank stands are built with no give what so ever having support beams hold the weight.
If the tank isnt leveled properly then that may be a reason but it could possibly be a stand that was incorrectly built having screws hold the weight rather than support beams. A single support beam of a 2x4 can hold roughly 800 pounds where a single screw can hold but a small fraction of that. I would first look at the construction of the stand. How large is this tank?
It's 45 gallons. I'm pretty sure the tank is supported by 2x4s. The tank is not level but that's because my floor is not level. I will double check though.