Well, I know those Oceanic sumps aren't cheap. What I am wondering is, why not take it back and geat a simple tank that you can build everything inside of. You will be eliminating a lot of headach and not having to purchase another pump.
I say this cause you bought a sump that came with a media chamber that you don't want to use, baffles that aren't high enough for your needs. I know if I bought a reef ready sump, I would not want to have to mod it or take half of it out.