Foam is for plate bottom glass tanks...ONLY.... It can and will do more harm than good when placed under acrylic tanks....foam is also unnecessary for glass tanks with bottom trim. If the tank is infact acrylic ur stand should have supports spaced every 24" square, minium. The tank should also be placed directly on the metal stand or on a piece of 1/2"-3/4" plywood on top the stand... if its unlevel, use shims to level it out from the floor 1st...then under that piece of ply inbetween the stand and tank if needed also... far better to use the appropriate amount of shims than to use foam/neoprene of any kind as it wont actually level anything, or support it properly.