...

-- hmmm, another KS plant with early nute depletion,..

... now, at this stage it's normal to see some lower fans starting to get tapped out, but usually not this much this early,... KS recommends monitoring the in-pot pH as well, and doesn't recommend using DI/RO water because all of the pH buffering minerals have been removed... this can put a strain on the soils own buffering capacity and lead to off pH, which in turn will restrict nute uptake,.. that said, it's
probably not off, or by much, she doesn't have that look,.. I'd watch carefully for potential P defc. as well, from my own experience and some others,... personally, I'd look into getting some organic nutes! Roots has an organic line, and General Organics is good too,.. I used a little of both grow and bloom to supplement,... I also recommend getting a soil pH probe, for direct in-pot measurements-

(the Accurate 8 is a good one),...