looks like a functional design.
Here is one i made:
Notice i have three chambers....the middle is the return, the outer two are feeds.
The chamber with the egg crate is going to house my sand and live rock(they will weigh down the eggcrate..it just floated in the flow test). Also I will have a turf scrubber hanging into this chamber as well.
The far right chamber is my skimmer station, if i go all natural...i can use this as a chaeto section, more LR, another scrubber ECT.
the middle is the return that feeds back up to the system.
OK now the science behind it....
Water flow is a big factor, you dont want water streaming through you sump/fuge at high volume. the slower water moves the better. Many skimmers have thier peak at 600gph. Scrubbers and chaeto tend to work great at around 400 gph.
Well i want water turn over as well in my system. Enter the middle return chamber...
I can effectively double the water flow through my sump by doing %50 through each side. and having them meet in the middle.
Ill probably have 500GPH on my scrubber/LR side(becuase im doing a large scrubber). and 600gph on my skimmer side(because thats what the manufacturer sudgests).
Since they meet in the middle..i basicly have 1100 GPH pumping back up to the top.
To control the flow...i'll have butterfly valves on both sides to control in coming water..and a control valve on the return pump to throttle it down.
Hope i gave you some productive thoughts.
BTW i think your current design is just fine.
