Hey Beth!
I suggest a smaller return pump (to minimize spashing noise) and bigger closed loop pumps. If you want quiet closed loop pumps, look at the Sequence line of pumps. The Dart and Snapper are both quite quiet.
Also, I don't suggest 30" tall. You'll need scuba gear to get to the bottom of the tank. 24" height at most IMO. You'll love the 30" width though.
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32"x32"x20" Cube-ish tank
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