Dr Clark recommends ozonating the oil from twenty minutes to 12 hours for the parasite mop up. I think that 20 minutes with a Nature Kleen would not be enough. I would go at least six hours. I ozonate our lightly ozonated olive oil for 6 hours with a machine that is 64 times stronger than the Nature Kleen so you have an idea. What you want to achieve is a good balance between having essential fatty acids that have not turned into ozonides and ones that have. It would take over 500 hours with a Nature Kleen to turn all the essential fatty acids in a litre of olive oil to ozonides.