I was a long time user of Pro Mix. I switched to a local mild compost mix. However, I'm surprised to see the addition of starter ferts now to the Pro Mix line. I went down and looked at an old bale I had and it doesn't list micro/macro or starter nutes as the site does now. I always remembered it being a clean peat mix. Perhaps new labeling laws in Canada? I stopped using it because of its lack of nutes. Wait, what is this thread about? Oh. Lower the 150. Kill the 600 for a week or two. At least you won't have many mold concerns when you flower with 20% humidity. What tev said.