Hi Kerry Thanks for your reply. Yep - I've mainly just been trying to keep the chocolate in temper. When batches have failed I have tempered it on a marble slab and most of the time that seems to work - though some lollies still get the bloom which is why I was wondering if it was something to do with the conditions whilst its setting - or something that I was doing to it. To be honest, the way we were taught to do it, I haven't been measuring the exact temperature of the chocolate at all. They just said to keep making sure the chocolate never felt too warm whilst it was being melted and to make sure to only heat it until it was just gone. If for some reason it failed, we were taught to put it back in the microwave and heat it for maybe another 30 seconds or so until it was completely liquid and thinner in consistency, pour 2/3 onto the marble slab and table temper until the 'sludgy' stage and then add back to the melted stuff - mixing and then reheating slightly with a heat gun if necessary to get rid of lumps. Its frustrating because that approach was working so well for months and then suddenly something has gone to pot and I can't work out what! Best Katherine