Looks good mate!
Interesting about the PAR. Wonder how much mine is at the bottom of the tank. Sometimes I worry it's too high, but it's on 60% acclimation mode and been on that almost since the start so maybe it's not that bad.
You've probably already seen it but this might be useful
Introduction to Flow
On my set up, I have the Octo set on 2 which is around 8x sump turn over for memory (based on just a rounded figure I use of approx 250L total tank, think the actual is 262L, but unsure if that also include ATO reservoir so I've always just rounded down just in case), but flow inside the DP using the nero 3 is around x26 (so around 4,628LPH on a variable setting so it ebs and flows a little bit).
From the quick research I've done it seems people want to have their water in the sump for longer (heating/skimming & so on). Supposedly back in the day it was something more like 10-20x turn over and that in recent years it seems preference is to have reduced, but I've seen people mentioning even as low as 4x now days.
It's probably a bit of a mixed bag but I guess it's whatever works for the individual and their tank. Any particular reason you've changed yours or just trying something out?