We mix our own fuel because it comes in at about half the cost of premixed varieties. The premix is about $15 per litre (about $60 per gallon) whereas we mix our own for about $25 per gallon. Have tried a couple of oils but find coolpower works the best and once again that isonly personal preference there is nothing wrong with the other oils. We just went to a chemical shop and purchased some measuring jugs for about $20 so we could be as accurate as possible and have never had a problem.