Im working on leveling the cabinet my 10g tank is going on but the top isnt flat and slightly off level. i know you can put styrofoam under rimless tanks to help even them out but what can i do about this regular 10 g 2 corners ar touching and 2 arent . and if i can put strofoam can i just use a foam core like project board? The kind that has paper on both sides with like half inch of foam in the middle? Im not sure where to get packing styrofoam sheets but the foam core board i can easily get at walmart or the dollar store