 I buy it at other places, and I've found it up to 120 parts per million on distilled water. Which, if you use distilled water for other things, medical and everything else, you need to know this. Because, you know, I told them, you're looking for a lawsuit. But anyway, you use distilled water, and you really have to be careful. Everything's totally clean. And I've used it on plants with aphids and plants with fungus and anything like that.