I refinished this old iron aquarium stand that my parents had but the top surface edges are slightly warped so that it rocks slightly on two corners. I'm wondering if the weight of the full 20 gal. tank with substrate and rocks will straighten it out on its own or if it will jeopardize the seals if the weight is applied to only two corners. Would it be a good idea to use shims under the back corner to stop the wobble or should I just let the tank settle?

You can place a sheet of insulation foam underneath it to help out the unevenness. Like this..
http://images.google.com/imgres?imgu...%3Den%26sa%3DN

Thanks dude. Worked great.