Need to build external overflow, any suggestions?

[Jason McK]

I plan on drilling a 1 1/4" hole in the back of a 40G tank. then create a box to put a Derso in

Similar to this taken from http://www.rl180reef.com/pages/stand...pipe_frame.htm


But I don't want to use a C-siphon or similar I want to drill the tank and create a box. Is this a good Idea. If anyone has suggestions or links that would be a lot of help.

Thanks
Jason