Uhm...I probably missed something, but there's a crack in the glass?!
Honestly, if I had that tank I would consider it such a shame to not have it one whole tank. I would buy a 6' 125 for the Eel. Cool to watch them swim one side to the other imo. That way you could put a few more predators in there put a giant chaeto filter in the sump. But that's just me. I would love to have that tank, I have always wanted a square tank with a center overflow.