[moocow]

I'm drilling my 58 gallon tank on the bottom panel for an overflow.
First off, how do I know how much flow I need? GPH? I've heard 7x-10x the flow.

If I plan to keep soft coral and soft polyps possibly hard stuff, what rate (GPH) should I aim for??

Where can I find over flow boxes?
I would like the kind that go from top to bottom and to do only one box.

Also, the idea of the intake pipe (inside the overflow box) is to be free flowing, so using a large diameter would make sense, right?
And the return to tank should be slightly smaller, right?

So how do these pipe sizes sound?
Return into tank- 3/4"
Drain to sump- 1"
This is what the All-glass kit contains for pipe sizes and bulk head at my LFS.