New tank...what is this plumbing?

[Lissa1987]

I think you missed this reply Lisa.
It looks pretty good as is.
I'd set it up as intended.

Unfortunately I have no need for a fresh water tank...The design and tank are definitely solid; I just don't have any freshwater setups...

 

[Dburr1014]

With that box inside you may not need the braces. Refill it and check for strength.
The hole in the glass in the box side could be used as the diy overflow to the sump. The next smaller box maybe a dsb?!?