I am building a stand for a 180 gallon acrylic tank I just bought. (Thanks to everyone for your advice on it. ) The stand I am constructing is square, but I am having trouble finding wood that is not twisted. The top and bottom frames do not sit flat on one another. There is a gap of about 1/4" in one corner. My question is, should I be worried about this? Do I need to rebuild the frame again so it is not only square, but true or can I just shim it up once I put the tank on it and roll with it? Thanks in advance everyone!