| In general, the number that you come up with for ammonia, nitrites and nitrates are either in ppm (parts per million) or mg/L, which is just the metric equivallent of ppm. Salinity is generally measured in ppt (parts per thousand) though if you ever need to know that.
What sort of water current do you have in your tank? I am wondering if your white film is not salt creep or if the salt is not dissolving completely in the water. Otherwise, it may have something to do with the aragamilk you are using...however I know nothing about it and so I cannot say anything about that for certain.
My thinking here is that something is up with your tank. I did the same thing as you and transported much of my live rock home in water and had some small ammonia levels at first, but then an almost immediate nitrate level of about 5 to 10 ppm right after the ammonia was processed. I am not saying that this is something really wrong with what you did, but I would really keep an eye on things, as you should do anyways I suppose.
The skimmer is probrably not picking anything up because there is not a lot of protein in the tank yet. They generally need some time to break in though so I would keep it on and keep checking on it often since it may just fill up all of a sudden. | 
