i want to build a tank that is 48''long 24''wide 24''tall. i need to know what type of glass i should use and how thick it should be. keeping in mind i'm going to need to drill holes in the back piece for the sump. i'm not sure but i'd imagine that would weaken the glass. i'm going to bring the back wall in 6 inches for the DIY background and then cut into that.so that will change the volume of water not sure if that matters or not. thanks for helping me figure it out in advance.