Yellowing leaves

you are having a lock out. your ph is off, first do a flush until you have a 6.0 ph reading. let your pot dry out for a few days. the first feed you do start at half your nutrient strength. add cal mag to you mix. aldo you will want to use a foliar spray of Epsom salts-( magnesium sulfate.) for faster absorption of the magnesium the plant needs your new growth of the upper will improve and start looking good again, your leaves that are damaged that are the bigger ones you will have to remove but only after you have new fresh growth. spray for a week only with the Epsom salts make sure your fan does not give the wind burn next. blow the fan on the tent wall. hope this helps