Sparky:
It appears that your process is thorough. The fact this creates a film is odd, it makes me suspect the bottles; but if you also have a funk in some fermenters, then I am not sure. I have no idea what this is, but I do know a method you can use to find out where you are getting it from so you can eliminate it.
I find that whenever I am checking out a system and trying to find an error in it, it is best to eliminate as much as possible and test each piece independently. Keep in mind two things: (1) It may be an environmental problem, (2) It may be a process, not an equipment problem. However, by eliminating equipment and steps, we reduce the odds of it being either.
Thus, I recommend the following:
First, keep excruciatingly detailed and careful records throughout this entire process. Include in this environmental factors - is it raining, is it snowing, what temperature is it outside, have you had a cold recently, did your dog drink any of the wort, what were you wearing, who else entered and left the brew room while brewing, what time of day was it, where did you brew at, etc.
Do an extract brew. Eliminate all of the steps that you can. Thus skip the mash and sparge. Buy a new hose for the process, and new cleaner. When you get to bottling, buy new bottles, use the new cleaner, and hand fill the bottles. If it is easier to keep things cold, maybe you should do a lager instead ... otherwise, try to control temperature as best you can.
If the batch goes bad - you have eliminated the mashing equipment, hosing, and bottles from the potential suspects. If the batch is good, then I would first do a second batch, and see if it too is good. If you get two good batches, then you have a lot more testing in front of you.
If you have two good batches, the next step would be to make a batch with your usual bottling procedure and your existing bottles. Same test applies here - if it is bad, you have a culprit; if it is good, do a second batch. If you get two good batches, move on to testing your mash.
If you can simplify your mash equipment and procedure any, do so, test it, repeat process.
Eventually you should get a bad batch. When you do, look at what was different about this batch from the last batch - in any of equipment, ingredients, or environment. Anything different is a likely culprit.
Once you have a list of culprits, you have two choices. 1) Replace everything in that list; or 2) Replace the most likely suspects in the list and test again from the last point in the process you were at when the batch went bad. I would classify hoses, plastics, anything that is not glass or metal, or has a scratch or ding as a more likely suspect.
If you replace those, and it still goes bad, you have two potential culprits - something else, or an earlier step. I would back up one brew time, eliminate the newly added equipment, and test again. Make sure it is not just environment or chance and that the brew just went bad on the third time through.
Now the special situation - it goes bad on your very first extract batch. Replace all the likely suspects and try again. If it is still bad, I am going to bet it is something in the environment and not in your equipment. At that point hire an inspector to come out and check your home for molds, toxins, and other potential problems.
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Finally, out of your entire process, I would say the most likely suspects are (1) mash tun, (2) tubing, (3) bottles, (4) environment, (5) bottles and caps, (6) process. The environment is going to be the hardest to correct for -- I would actually hire someone to come out and check my house for molds and similar problems. The others are going to take testing and checking to discover which is the cause, but you can fix them. Also, it is possible for mildew, mold, bacteria, and other suspects to evolve a resistance to sanitization chemicals ... great brewer in the sky help us all if this happens.
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Good luck! Let us know how it goes.