Hi all. I have a normal 55 gallon tank that I am designing a tank lid for but am worried about my measurements. I get different results than my husband and this freaks me out. The last thing I want is to order and pay for this and I be wrong. Can someone help me out on the inside of the lip measurements of a standard 55? And if you are feeling froggy... I have a CPR CS 150 over flow. Let me know if you have any ideas to get the proper numbers.