Mr. Wilson,
First of all thank you for that properly constructed post if every single person on this forum was like you I don't think I would ever stop reading
. I will break my "No more posting" post as there are finally some factual intelligent comments on here.
The only one major difference between what you have described and what takes places in the average reefer's sump is that almost in all cases the skimmer is never fed by the return. In the future I might design my sump like this as its an interesting concept and I'm sure it would save energy/ increase efficiency. Just out of curiosity do you have any photos of your sump as I would love to take a look?
Now that being said, as most sumps are not like this and include a sump volume with multiple apparatus drawing water out of that volume (and not being plumbed in line). We can determine that some of this water is leaked and gets pumped back into the main tank has to be dirty (as there is no way you could 100% clean this before it makes its way back).
So if dirty water is being plumbed into the tank anyways why not increase the flow so there is constantly a new supply of DOC and surfactants for the skimmer to skim off? Also with the advent of Biopellet reactors, Zeovit and other nitrate/ite/NH3 sinks would it not be more beneficial to have a higher turn over to supply fresh dissolved (As compared to surface) organics to these reactors?