lol You seemed to have missed a very pertinent point, Iron. This is a established tank, meaning it has already been set up and stocked. Although if this were a new, empty tank, that would be a good idea to take example from a reef-ready tank on where to set up the overflow box and how to drill. Unfortunately Zack, there is no safe way to drill a loaded tank. Even if you could find a way to isolate the area you would be drilling, the drilling under pressure would likely cause cracks or a complete break. As Chris stated, you can buy a hang-on overflow and get the same effect as a drilled overflow in your tank, although there is more of a risk of having either the display or the sump overflowing for one reason or the other. If you match your components properly, the risk of this is reduced dramatically, so be careful which overflow/return pump you get. If you go this route, make sure your return pump is just a tiny bit larger capacity than your overflow, you can tone the return down with a ball valve to fine-tune the system. HTH
