I am trying to decide on which return pump to use for my current 75 gallon build. I've looked around a lot and it seems there are a lot of answers like "well it depends on your overflow." Well in my case that's wrong because my overflow has a lot of headroom (it's a custom glass-holes.com one that has max 1500 gph!), so I can get pretty much whatever pump I want up to that limit (which is way too high). So how many GPH rated pump should I get? I was thinking a mag drive 9.5 or Quiet One 4000, but the girl at my LFS told me that's probably even a little bit too high. I ran a mag drive 7 on my 55 gallon with a 10 gallon sump, and so I figured a 9.5 might be good. What do you think? Another question, I have 2 3/4" return kits (each one is rated to like 1100 gph), should I install both just to leave myself headroom (and allow very low resistance) or just one?