I need advice

Leaves will typically droop in lack of light. what are you running for medium/nute?

they droop in dark. that's normal. They should 'pray' in the light. A time lapse may show them rise and fall a bit, but in dark they only fall. it's possible to overwater if the pot is too big for the plant, even if it takes a long time between watering. Just depends on the radius you watered. If it's been since sunday, that must have been saturated, eh? probably stick to a slightly larger radius of the canopy when you water. If you've been fertilizing the whole time, the outer area has built up nutrients too. if that is the case, give a good water-only hydration around outside, and carefully water where you should too, but less -- likely absorbs enough before you get to it.. After that, stick to ~canopy-sized radius. you've added cal-mag and it's not likely a deficiency in either of those elements. this adds to the buildup.

She looks to be more sensitive than her sister.. Hard to tell from the colours, but the signs are of over-watering. Water when the lights just turn on, so the plants have the entire day to "digest". Make sure to allow the soil to 95% dry out between waterings. She hopefully will work through this early-age struggle, and be close behind her sister.

Plants sleep at night and they droop their leaves down, they don't droop so much in flower