Opinions on my sump setup please

[gregzz4]

Can't see enough as your pic is dark
Speaking as one who is now working on a 2nd sump build, I'll say;
Try to maximize your space while keeping it simple.
Having removable socks that aren't obstructed by hardware will keep you happy to perform regular maintenance.
Keep access to your skimmer and reactors open for the same reasons.
Can't say much about the new blocks you are using, but have read good things about them

The deeper my return section is, the quieter my pump becomes