From a recent study, major components of Skimmate are:
Aluminum - 45ppm
Calcium - 2200ppm
Copper - 1.5ppm
Iodine - 19ppm
Iron - 25ppm
Phosphorus - 37ppm
Silicon - 24ppm
Sulphur - 662ppm
Interesting to note is that the sludge that builds up inside the skimmer is a better export mechanism than the actual skimmate....
The Calcium export is disappointing because that needs to be replaced. An example element in the sludge is Calcium where it's found at the incredible concentration of 37,000ppm.
Again... this was a very small sample size and your results may vary.