Hi, first time grow. Indoors using a 3 x 3 tent. I am doing a flood and drain hydro grow using PVC pipe. I'm using Peters Professional Hydroponic 5-11-26 and bought and added CalMag a few days ago. I did have them in the tent without any exhaust system up until about a week ago. I have been playing around with flood rates and times, I now have it where the pipe fills and drains every hour, it takes about 2 minutes to fill and then the pump cuts off. Any insight on the brown spots would be appreciated. This is 8 Ball Kush