This is 1.5 weeks into flowering in a 4x4 tent. The temp stays at 77 and sometimes rises to around 79 so heat is not a problem. I don't understand what is going wrong. I have an 8 inch exhaust at 720 CFM. The HPS is around a foot and a half to two feet away. Im not over or under watering. What could cause the top leaves to curl like this?