I hope you understand, that in replying to your thread I wasn't trying to tell you what to do, I was just stating what I have learned myself. I don't know where you are from, but where I am from both the EPA, and the CDC, have said that if PBO is used in small amounts it isn't harmful. But those same agencies have repeatedly said that about so many other pesticide additives that have later on been proven to directly cause some form of Cancer, so I simply cannot trust those agencies, and that's especially reaffirmed when there are other studies by well known Cancer Researchers that have proven those agencies absolutely wrong! Anyhow... for me, it very important that I evaluate anything I might use to grow my cannabis because the people that use the cannabis I grow shouldn't ever need to wonder if the medicine I am giving them is laced with something that could cause them even more problems!