tank setup q's

[spikehs]

Hey all,

I am debating on down-grading my 80gal tank in favor of a smaller 40gal. I love my 80 but, being a student when i move out, a 40 gal will be MUCH more practical. My 80gal doesn't have a sump or anything, which i really would like to have, so this will be reefready with ~20gal sump Now i haven't even really decided if i have to do this (i should be upgrading not downgrading!!). But thought i would gather some opinions first. The tank will be a mix of most corals....

1. i am currently thinking of the 36x18x15 from inter-america, but 15inches seems a little shallow front to back, would 36x18x18 make much of a diff?

2. what size pump should i get? the sump will be at most 4feet below the tank. Since the tank is smaller i would like to avoid powerheads (after i went and collected 2 more for my 80!!) I was thinking around 1000gph?

3. How many returns should i get and at what size? i was thinking 2, but wasn't really sure on the size, 1inch?

Thanks a bunch,.

Sean