My plants are 4-5 wks into flowering and the upper fan leaves on 1 plant just started to get little tiny yellow specs/dots on them. What is this? Specs: soil grow, 400hps, 90 temps ( i know not good, im working on that), lite on the nutes (advanced), watering every 2-3 days.......otherwise its ok nice budding......any advice what be helpful........thanks in advance