Thanks for the input guys... I was leaning towards external but when I got the quotes back external was $350 more than an internal.
The tank I am planning to get made will be 80Lx36Dx24H and the overflow will be on one of the sides (peninsula style). It will be coast to coast wether it ends up being internal or external. If internal it will be a few inches tall and not the whole height of the tank.
Do the standpipes have to be in the center of the overflow or can they be put to one side?
Here is a pic of my current tank. The new tank will be put in the same location and the overflow will be on the right side of the tank/pic.
[MENTION=4608]SchnitzelReef[/MENTION] That is some nice plumbing you did, I'm thinking of doing my returns similar.