Sorry about being too vague. My plants are in flower, i currently water once a day 15 minute flow in ebb an flow in a 4 by 2 grow tray. My plants are about 20 inches tall and are in 4 inch rockwool cubes that are surrounded by hydroton clay rocks.400W HPS. I keep my PH around 5.8 to 6.0. my temperature is a little low in my bud room. Around 45-50 degrees. Humidity i am not sure but i do have a outtake fan. The only nutrient i use is Maxibloom, i put 4 tsp in my 20 gallon reservoir. I only put about 6 gallons of tap water in the resevour because it is all i need. I am going to start watering up to 3 times a day once the roots expand a little more. I feel as if the rock wool soaks up too much water. After reading this does anyone know what these brown spots are? I am desperate to fix it and help my ladies grow as healthy as possible.