It is not the "film" but the air/water interaction. We are not talking about something that takes minutes, this is not a skimmer. We are talking about the surface tension of the water and how quickly that sheet of water can be renewed. Double the width of the overflow and you double the renewal rate.
no, we are talking about the same thing. by 'film' i mean the same thing you do by 'surface tension'. doesn't have to be thick and gooey to be a 'film' as you might be thinking, think of it as a microscopic film, even if the individual proteins are few and far between. and it is kinda like a skimmer. think pre-skimmer. the atmosphere is 1 big rotating bubble with a squeege (the overflow) on one side to peel proteins off.
the minutes/seconds i am talking about is pretty much the same thing as your renewal rate, i was just taking it a step further and applying that to tank size to actually mean something and put it in perspective. for example doubling your money sounds great in theory, doubling 1000 bucks is something and worth some effort. but doubling a penny is nothing.
The idea is to move as much of the protien away from the display as possible, as fast as possible so that it does not have a chance to interact with other protiens or compounds in the tank.
i've been looking for proof for or against this but haven't found it so consider this part pulled out of my butt: i've wondered if long chains hanging from the surface have a chance at grabbing other chains that aren't close enough to the interface to get grabbed on their own. seems that clumping would have to be possible, otherwise we wouldn't be able to get a stable foam head in the neck. not sure how polar these are though and how that affects attraction/repulsion. i have some vague memories about this very thing from bio (i can still see the diagram in my head).
Your looking at it as a "surface scum" problem, not a chemical and physical bonding problem.
no, i just called it 'surface scum' because it's a good generic term to use. 1 single protein stuck to the surface is 'scum on the surface'. i am not talking about an oily slick on the surface that is visible to the naked eye and takes days to accumulate.
But you simply can not draw the line at some arbitrary point and say "I think you guys are making too much of this".
but you can draw an arbitrary line and say it is important? this is *exactly* why i am trying to put numbers on the refresh rate to put it in perspective. if my rough numbers said that a full length could clear the surface every 10 seconds vs a smaller one that took 5 minutes, then i would be driving the bandwagon. but when it's probably closer to 10 seconds vs 30 seconds (i figure most conventional overflows are 1/3 the linear length of a full length) it's not that hard to discount.
Like I said, I pefer to err on the side of overkill.
so you'd rather have 10 50w heaters than 2 250s? a 10' skimmer vs a 6' skimmer? a 10" dsb rather than a 6" dsb (assuming you like dsb), build your stand out of 6x6s rather than 2x4s?
so let's back up and look at the pros and cons.
pro: it *might* give you a tiny boost to skimming. heck, might give you a big boost in skimming if you have a *very* slow turnover on a huge wide/long shallow tray tank (so that we were talking 5 minutes vs 15 minutes) and you have a horribly undersized skimmer. kinda like what most greenhouse ops i've seen have been like. then you might have something, but that doesn't mean it translates to a conventional home tank. also better aeration if you have an aeration problem (also not an issue in conventional home tanks).
con: it costs money in glass/acrylic/plumbing, time and effort to cut, drill and install, takes up a large portion of the tank, blocks light, and makes it difficult to hang stuff from the back (waveysea/autofeeders/vortech/...)
even if it did give you a noticeable boost in skimming, i'd say put that money towards a slightly bigger skimmer instead. it'll be much more likely to give you that better skimming you are looking for, won't take up tank space, will react to 'issues' faster than a smaller skimmer, and will get you back better resale value if you decide to sell stuff.
My 1/16" is just a guess by looking it it. If I measured it or did the math I may find that it is closer to 1/8" or so. In any case it is very thin and silent. I am also guessing at the 2300 
