Redoing sump. Need more input

[Bsixxx]

long story short, I killed my filtration and all bacteria in my sump. Basically making my tank restart and unable to keep up with the bio load.

Anyways, I am redoing the sump because the previous one was trash, because I was lazy. Now I am paying for it, so I re-did and am currently stuck at this point.

First and second photo is how it currently sits and how I expect it to be.
Third and fourth is what it used to be.

I will also be adding in an aqua ultima ii filter down the line, but just want to get sump back up and running.

Looking for feedback as to make better or if its good so far.

 

[BIG-G]

Couple questions. Is the first chamber sealed? Where will the return pump go? After the deep sand bed?

I used to run very complicated sumps with baffling and multiple chambers.
I’ve since changed my opinion.
Simple is best. Especially for freshwater.

There may be a need for different chambers in a saltwater system to separate skimming and refugium, algae scubbers etc...
But for freshwater I like just a simple mechanical, then biological and a place for the return and heaters.
The easier it is to do maintenance the more likely I am to actually do it.