If you are doing mainly LPS and softies with very few SPS, I would go with a sandbed. If you go barebottom you'd have to jack up the flow to keep detritus suspended (which your LPS and softies wouldn't like) or slow down the flow so you can suck it up off the bottom (which you SPS wouldn't like).
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32"x32"x20" Cube-ish tank
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