Got the whole frame welded out, added the missing pieces and fit up the lip for keeping the glass in place. Mocked up the corner joint to make sure that it was even and square.
This is kind of what i'm thinking for a sump design. Hoping to find an old 90 gallon to convert to the sump as the current 50 gallon will probably be a little small for the 1500 or so gph which will be running through it.