this is right from glasscages.com
http://www.glasscages.com/?sAction=AqWarranty
This is for the GLASS aquariums
All aquariums must be set up on commercially manufactured stands only. A sheet of 3/4" Styrofoam (reaching completely side-to-side and front-to-back) must be placed between the tank and the surface of the stand. Aquariums should not be set on wood furniture, stereos, televisions, or other surfaces that have not been designed to support an aquarium. Setting up the aquarium on a homemade stand or on a surface such as the ones mentioned above can result in stress breakage of the side or bottom glass panels of the aquarium. Breakage is NOT guaranteed. It is very important to follow the INSTRUCTIONS:
Call them up. This applies to rimless glass tanks, and rimless tanks only. Or rimmed tanks in which the bottom glass sits flush with the bottom of the rim. The foam is to eliminate POINT stress, that will cause the bottom to fail. I cannot pinpoint exactly when the inaccurate information concerning the use of foam under tanks started, or where. But I imagine it started not soon after rimless glass tanks started gaining popularity, and by word of mouth, the information was corrupted to mean something entirely different. Back in the "days of old" no one had foam under their tanks, even acrylic tanks. This is bad information.
And as long as going off on this, might as well go the rest of the way. The proviso on stands is exactly what this thread is all about: It is not easy to make a stand that has a dead level, dead square, dead flat surface, at home-- with out a good arsenal of tools for the task. And with any tank, regardless of design, a DIY stand voids the warranty.
A rimless glass tank, can be put on a stand supported only around the outside edge of the tank if 1: The bottom glass is thicker than the side glass, (and this is represented by the second thickness "bottom thickness" that I include in answer to how thick does the glass need to be for a rimless X" x Y" x Z". 2: The bottom glass is of greater thickness, and is raised inside the sides. Do not try this at home, if you do not know what you are doing.
A rimmed glass tank, does not, and has never required a top on the stand, only the rim of the stand, and of that, only the corners need to be supported, however, it is a good move to have the whole perimeter of the tank sitting on the stand, within reason. Small gaps, paper thickness, even credit card thickness will not present too much of a problem as long as the corners sit square and flush on the stand. So if the corners are not on the same plane, or the tank corners do not sit on the stand, as the case here, the tank is in jeopardy, and foam will not correct the problem. The foam is a cushion, not support. If not sooner, then later, the tank will give out. It may be a broken panel, or a popped seam, or both.
J
