AsNoriuanswered grow question 2 years ago Either your ph pen is lying , it happened to me many times, have a habbit to recalibrate regularly.
Or those girls need a bit higher ph, calcium absorbtion issues, and by chart 6.5 only starts good absobtion, to plus magnesium too.
Try to raise your ph to 6.3 or 6.4.
After many grows i dm in love with 6.3, was in 6.4 boat tor long too.
Your end is near, i would not stress a lot, but during flush in soil, people go from growing range of 6.2-6.5 to 6.5-7.0 even, fades quicker, brings colours acording .... Kind off ;)))
Happy Growing !!!