I am building a stand for my aqueon 210. I am using using a simple design with 2x6 for the frame. The tank is 6ft long. I am wondering what others may have experienced in regards to the crown on the boards. At 6ft long it is next to impossible to find a board that doesn't have some sort of crown. Right now I have them placed crown up but the tank does not make contact in all corners. There is 3/4" playwood on top of the 2x6s as well. Any advice would be great!