
Trey...need more pics of whole plant, age, if you're pH'ing the water (DI/RO has no buffering minerals in it, so any pH'ing will produce wild swings and instability),... KS doesn't recommend using that pure of water partly for this reason... have to taken in-pot pH measurements? Whether it's KS or Mephisto's add-in mix, monitoring the pH is very important to ensure proper nutrient uptake,....
..first pic looks like Ca defc., so start that Ca-Mg right away, including it in your DI water... Second, I'm with Nammy, that looks like typical fan tapping for N mostly, causing that overall yellowing,.. this is why I need whole plant pics and age, to see if it's starting too early in bloom cycle, which would indicate depletion of N sources in the soil,... some mild organic grow nute's will help if this is the case...