Hmm, its a bit like phoning the Doc and saying I don't feel so clever whats up with me? , at a rough guess it reads like its some sort of fungus growth if you leave a pot of jam out with the top on it soon grows a white fungus like growth on the top , the problem is if you put the yeast in while the water is still hot it just kills the yeast , I have started some 10 Litres of Pineapple this morning and its going like the clappers , before putting it in a demi john I always use a big plastic container with a good lid with a weight on top for the first 2 days of fermentation as many times its so vigorous it just blows the plastic bag off the demi john like an erupting volcano!, in most cases fermentation should only take about 7 days or so depending on how much sugar you use , once its in the demi john it takes about 3 weeks for all the sediment to go to the bottom ,I siphon it off into another clean demijohn top it up and put the screw top on , I really wish I could help but without seeing it ,bit hard to tell , what makes it even harder I have never ever come across something like that before ,the best thing to do in my opinion is taste it ,if its sweet or sweetish the yeast has not worked , loads of advice on Google ,forget all the fancy ingredients , Sugar,water,yeast and the fruit or juice of your choice ,if I was Billy I would try just a small batch of say 5 litres as an experiment ,by the sounds of things the first try ain't turned out right , but I was just the same when I started out many moons ago , the grape fruit juice in cartons is just the job for a beginner, loads video's on Google on how to go about it , once you get in to it its as easy as falling off a log