Heh! Great name, tunatamer, and welcome to TRT.
The issues most likely to present problems for you involve how much you have to feed your fishes, the substrate as
crushed coral, and the presence of the fluval. These factors all lead to a large amount of both fish waste and uneaten foodstuffs, as well as plenty of surface area and digestive bacteria that allow both the waste and any uneaten food to be quickly converted into available nitrate and phosphate for the growth of your
Caulerpa spp. of macroalgae as well as phytoplankton and misc. other microalgae. This in and of itself is not a problem, but excessive growth of macroalgae, in addition to no real means of breaking up and removing
Gelbstoff from such a leaky macroalgae (
Caulerpa) allows an accumulation of these byproducts of macroalgal growth to concentrate on the surface. In addition, certain spp. of microalgae will grow on interfaces such as surfaces of rock and sand, the glass and at the interface of the ASW and air. This will be a good bit of your films that are forming, but does not include the possibility of films that sometimes include other organic compounds and calcium carbonate could be forming at the surface as well.
In systems that are primarily fish and/or fish and macroalgae, this does not present a real problem, as you are exporting nitrate and phosphate when you remove the Caulerpa's biomass from the system, leaving the cosmetic issue only from the accumulating Gelbstoff and misc. other organics at the surface. However, in systems that contain corals, especially stony corals, the accumulation of this potential level of nitrates from the available sites to trap leftover food and wastes for aerobic nitrification (the fluval and the crushed coral substrate) will lead to reduced calcification in stony corals and browning of their coloration as these substances increase both population density and overall numbers of zooxanthellae in autotrophic corals. We strive to keep our corals colorful and improve their growth and calcification rates, and high nitrates are the bane of our desires to promote this. Remember that zooxanthellae are nothing more than algae, and as such, these endosymbionts respond to high levels of nitrogen and phosphorus the same way that any other autotrophic algae would, by increasing their numbers...
The easiest way to reduce the production of nitrates and accumulation of phosphates in marine systems is to limit imports of substances that can decompose to form excessive nutrients, and to maximize the export of these same potentials for excessive nutrients. Potentials for limiting imports includes reducing the numbers of fishes, or reducing the frequency and quantity of the food we provide for the fishes, using water that is free of nutrients for evaporative replacements (RO/DI), and providing and/or preparing foods that are low in excessive amounts of nutrients (e.g., rinsing frozen foods with RO/DI prior to feeding). Maximizing exports means reducing the number of sites that excessive foods can collect and decompose in the tank (the size of your granules of the substrate, the fluval, etc.), removing the substances that can decompose to nutrients before the dissolve into the water (aggressive skimming, Granular Activated Carbon=GAC, resins, etc.), macroalgae harvesting**, etc.
For you currently, I would recommend aggressive skimming and the use of a
surface skimmer to collect surface water and the organics that are accumulating there to export the materials and algae, etc., from your water column. Directing water flow at the surface will improve oxygenation in your tank, but will redistribute the organics that are already concentrating there. Rather than have you redistribute these substances, I would recommend that you take advantage of the natural tendency for these compounds to concentrate at the air/water interface and collect them with a surface collection overflow. Once collected, skim them out of the water via a foam fractionation column. This along with the use of GAC will not only remove the potential for algal blooms, but will make your water much clearer*
Much of what you will need to do will depend on what your goals are for the system. Could you tell us more about your system and where you're going?
HTH
*
look through your tank from one end to another and look at a piece of white paper, Does it look white? Even better, get a color chart of light yellows from a paint store and do the same, which ones can you see?
**
Macroalgae harvesting has its own issues, depending on which macroalgae you use to export excess nutrients, we could make things worse for your system in the long run, but this will again, depend on what the goals are for your system. We could make (and have done so in the past) entire posts on this subject. Much of the decisioin to do this will depend on what the goals are of the biotope you are trying to emulate. 
Vince aka VINNIE 
