well u get root rot from over feeding..... you roots can only take up so much nut's when it cant take anymore up it just stays there then u feed more n more pretty soon u get ROOT LOCK... so your roots lock up n dont feed... then they ROT..... u can use flora clean it is a general hydro prduct run for 3 days then 25% nut strenght.... n u shouldnt start final flush till week 7...